This list only factors in passers' work after their respective free agency signings. Here are the best quarterback free agent additions in NFL history.
The controversial quarterback's post-prison career did not register on the same level as his Falcons years, but Vick spent three-plus seasons as the Eagles starter and was 2010's NFC Pro Bowl first-stringer. Andy Reid signed Vick after his two-year prison term ended in 2009, and when the Eagles traded Donovan McNabb in 2010, Reid turned to Vick. The inaccurate passer delivered his best completion percentage (62.6 percent) and TD-INT ratio (21-6) under Reid and led the Eagles' 21-point comeback over the Giants en route to the NFC East title.
A four-year Bears starter who piloted two Chicago playoff offenses, Harbaugh signed with the Colts in 1994 but entered the next season as the backup to 1995 addition Craig Erickson. Harbaugh, however, regained the job from the ex-Miami Hurricane star during what became his best season. Harbaugh led the NFL in passer rating, made his only Pro Bowl, guided the Colts to two playoff upsets — the second over the top-seeded Chiefs — and had them within a nearly completed Hail Mary of Super Bowl XXX. He got the Colts back to playoffs a year later before being traded to the Ravens and Chargers.
The Rams' "Greatest Show on Turf" nucleus was not the same after Super Bowl XXXVI, but the crew enjoyed additional success thanks in part to an ex-Saints and Falcons castoff. The Rams added Bulger to their practice squad in 2000, and by 2003 injuries and ineffectiveness led to Kurt Warner's benching. Bulger replaced Warner in '03 and by season's end he was 18-4 in his first Rams starts. The new Rams QB find made two Pro Bowls and guided the Rams to 2003's No. 2 NFC seed. Bulger remained St. Louis' QB until 2009, but the late-aughts Rams' struggles cloud his career to some degree.
Fitz has played zero playoff games in a 15-year career and is an eight-team veteran. But he has started 97 games for five teams who have signed him as a free agent, consistently giving teams either a capable starter or a high-ceiling (re: his super-Fitzmagic-y 2018 Bucs work) backup. Fitzpatrick's 9.6 yards per attempt with the '18 Bucs is tied for eighth all time. Fitz has a losing record with all but one team that has employed him but somehow managed a 20-13 TD-INT ratio for the 2019 Dolphins, which sported one of the worst rosters in modern NFL history. The 2005 Rams draftee is set to play into the 2020s.
While Dilfer made 37 starts after his one-season Ravens cameo, he's here almost entirely because of what he accomplished on a one-year, $1 million Baltimore contract in 2000. After his six-year Bucs tenure ended with rookie Shaun King taking his job, the former top-10 pick supplanted struggling Ravens starter Tony Banks a year later. Banks failed to produce a touchdown drive in his final four starter. With considerable help from the Ravens' historically great defense, Dilfer then went 11-1 as a starter. Following their Super Bowl XXXV rout, the Ravens replaced Dilfer with Elvis Grbac, who retired after the 2001 season.
A scab role during the 1987 strike landed Kramer a CFL gig, and he returned to the NFL via low-level free agency deal with the Lions in 1990. While the Lions invested a top-10 pick in Andre Ware and had veteran Rodney Peete, Kramer led the way the last two times the Lions won their division (in 1991 and '93). He took over for an injured Peete in 1991, and in Detroit's most recent playoff win, he threw for 341 yards and three TD passes in a 38-6 Round 2 conquest over Dallas. Kramer's off-and-on starter role convinced the Bears to sign him in 1994. He still holds Chicago's single-season TD pass record: 29 in 1995.
After nine seasons in Canada, the six-time CFL MVP and popular but ineffective 1980s NFL QB received a shot with the Bills in 1998. However, Buffalo soon traded the No. 9 overall pick for Jaguars backup Rob Johnson. In their three years together, Flutie (21-9 as a Bills starter) outplayed Johnson (9-17) at every turn, the 5-foot-9 icon sparking the '98 and '99 teams to playoff berths. Buffalo benched Flutie for Johnson before a 1999 wild-card game (the Music City Miracle), but he started 16 Chargers games in front of Drew Brees in 2001 and played until age 43, his final appearance featuring this rare NFL act.
Coming to Denver after six Arizona years, Plummer led the team to three straight playoff berths from 2003-05. Mike Shanahan replaced Brian Griese with Plummer, giving a player eager to leave a bad Cardinals team a seven-year, $40M deal. Shanahan deployed Plummer on countless bootlegs, and the Broncos went 39-15 in the mobile passer's starts. Plummer made the 2005 Pro Bowl and became the first quarterback to beat Tom Brady in the playoffs, helping the 13-3 Broncos to the '05 AFC title game. Shanahan demoted Plummer for Jay Cutler in 2006, but the former retired in '07 instead of accepting a trade to the Bucs.
The Buccaneers outbid the defending Super Bowl champion Ravens for Johnson's services in 2001. That signing probably altered the early-2000s NFL. The former Vikings and Redskins QB, who signed a five-year deal worth $28 million, helped the Bucs' dominant defense stampede to the Super Bowl XXXVII title. The 34-year-old passer made the 2002 Pro Bowl and threw five touchdown passes in the playoffs. Tampa Bay has not won a playoff game since. Johnson was a four-year Buc; the Ravens' defense had to settle for Elvis Grbac and then Kyle Boller.
Following retirement No. 2, Favre went from New York to Minnesota. An arm injury limited Favre with the Jets; he recovered in 2009 to have one of the greatest age-40 seasons in American sports history. Favre signed a two-year, $25 million deal and threw 33 touchdown passes — his most since 1997 — and elevated the Vikings' offense from 17th in 2008 to fifth in '09. The Vikings swept Aaron Rodgers' Packers that season. A Favre late-game INT proved costly in a loss to the Saints in the NFC title game, and his 2010 season did not go nearly as well. But the Hall of Famer made a major impact during a short Minneapolis stay.
The longtime Eagle skipped the 1996 season, briefly retiring. Dennis Green lured him back to football in '97, despite merely a $425,000 salary (which was lower than the Saints' $700K offer). A prudent investment. After Cunningham replaced an injured Brad Johnson and led the '97 Vikings to a wild-card win in New York, he teamed with rookie Randy Moss to help the Vikings set the NFL scoring record in a 15-1 1998 season. The 35-year-old QB threw 34 TD passes in his lone All-Pro slate. Though the Vikes fell short of Super Bowl XXXIII and Cunningham was gone from Minnesota by 2000, he redefined his career in one season.
Substance-abuse issues led to the former top-five pick's Panthers downfall, but he soon stabilized a Giants team that had lacked a reliable passer since Phil Simms' retirement. The Giants gave Collins a four-year deal in 1999; he had them in Super Bowl XXXV a year later. His masterpiece came in a five-touchdown pass NFC championship game — a 41-0 romp over the Vikings. Collins, who also led the Giants to the 2002 playoffs, was Big Blue's starter until they acquired Eli Manning in 2004. Collins caught on with Tennessee in 2006 and resurfaced at 36 to usurp Vince Young and led the '08 Titans to the AFC's No. 1 seed.
The Panthers initially acquired a seven-season starter on a two-year, $4 million pact in 2003. Delhomme delivered immediately, leading Carolina to its first Super Bowl that year. The Saints gave Delhomme scant work in four seasons, but Aaron Brooks' former backup guided the Panthers to three NFC South titles and two NFC championship games. Delhomme went punch for punch with Tom Brady in Super Bowl XXXVIII, helped Steve Smith begin his Hall of Fame case, made the 2005 Pro Bowl and earned two Carolina contract extensions. Despite a five-INT outing in the '08 playoffs, the former UDFA was a free agency success story.
The Eagles' Foles reunion ended up being fairly important. After unmemorable stays in St. Louis and Kansas City, Foles was thrust into the role of quarterback for the NFC's No. 1 seed in 2017. Carson Wentz's December injury made the Eagles underdogs in both playoff home games; Foles surpassed all expectations. The sudden RPO warlord combined for 725 yards and six TD passes in wins over the Vikings and Patriots, securing Super Bowl MVP honors and a "Philly Special"-themed statue. Getting a lot done in 13 Eagles 2.0 starts, Foles also elevated a listless 2018 team to a final-eight appearance.
The 49ers adding Garcia in 1999, after his five-year Calgary stay, proved critical. Aeneas Williams' vicious hit on Steve Young ended his career that September, and Garcia's heir-apparent run began early. From 2000-02, Young's elusive successor made the Pro Bowl. He led the 49ers to the playoffs during the '01 and '02 seasons. After separating from Terrell Owens, Garcia also quarterbacked postseason games with the Eagles and Bucs and wound up in the '07 Pro Bowl under Jon Gruden in Tampa. Garcia played for five teams but was never traded, ensuring a spot in free agency lore.
Testaverde's first post-Bucs stop was in Cleveland, and he started in the Browns' most recent playoff win. The Browns gave the former Heisman winner a one-year deal in 1993 to back up Bernie Kosar, just like in their days at "The U," but Bill Belichick surprisingly cut Kosar that October. Testaverde quarterbacked the Browns/Ravens until 1997, and on a mere one-year, $1.5M deal, had the Jets in the '98 AFC title game. He made a Pro Bowl with the Ravens and Jets, steered Gang Green to another playoff berth and held both the Ravens' and Jets' single-season TD pass marks (33 and 29) for 23 and 17 years, respectively.
The No. 1 overall pick in 1971, Plunkett soared into the bust realm after shaky stays in New England and San Francisco. But after spending two seasons as Ken Stabler's backup, Plunkett began a remarkable comeback tale. The Raiders traded Stabler for Dan Pastorini, but with the latter not panning out, that left Plunkett in command. Although never a Pro Bowler, Plunkett threw seven touchdown passes in the 1980 playoffs and was Super Bowl XV's MVP. Despite Al Davis repeatedly trying to make 1980 first-rounder Marc Wilson happen, Plunkett was at the controls for the L.A. Raiders' dominant Super Bowl XVIII victory.
Gannon could not replicate Plunkett's Super Bowl success, but he was a better quarterback. The Chiefs kept middling starter Elvis Grbac over Gannon, who played well when called upon during his four-year Kansas City stay, leading the latter to Oakland in 1999. The Raiders gave Gannon a four-year, $16 million deal; he gave the Raiders their best years since the early 1980s. Gannon made four Pro Bowls from 1999-02, was twice the All-Pro quarterback and won an MVP at age 37 while leading the veteran-fueled Raiders to Super Bowl XXXVII. Gannon's work towers over every post-Plunkett Raider passer.
Blanda spent 10 years with the Bears but retired in 1959 after George Halas resorted to mostly using him mostly as a kicker. But once the AFL formed in 1960, Blanda signed up and made the Oilers the league's first glamour team. Blanda and wideouts Charley Hennigan and Bill Groman lit up scoreboards. Houston won the AFL's first two titles, coming within a double-OT loss from a league-opening three-peat. Blanda's 36 TD passes in 1961 remained an AFL-NFL record until Dan Marino's 1984 work. Blanda spent seven years as the Oilers' QB and played until age 48 as the Raiders' kicker.
Denied an opportunity to be an NFL quarterback upon coming out of college in 1978, Moon became a five-time Grey Cup champion in Canada. That ignited a 1984 bidding war the Oilers won with a salary north of $1 million, which made Moon the NFL's highest-paid player. He quickly became one of the NFL's best passers, made five straight Pro Bowls in Houston and guided the run and shoot-based Oilers to seven consecutive playoff brackets. After a trade to the Vikings, Moon made the Pro Bowl at 41 upon signing with the Seahawks — the runners-up in 1984's Moon sweepstakes — and played until age 44.
Arguably the best to ever do it, Manning is No. 5 here because his Colts work is excluded. His post-free agency Denver tenure only lasted four seasons — and the final one-and-a-half years featured a decline likely accelerated by the neck injury that made him a free agent in the first place — but Manning's dominance with a fraction of his physical abilities will help his best-ever case over time. So will the Broncos' post-Manning swoon. Manning's five-year, $96M Broncos deal preceded his QB-record sixth and seventh All-Pro honors, 2013's stratospheric display at age 37 and two Super Bowl berths. A lot of commercials aired too.
The Browns acquired Dawson via trade from the Steelers, but Paul Brown cut him after two seasons as a backup. In 1962, the Dallas Texans added the 27-year-old passer and saw him lead the team to an AFL championship that season. Dawson became the face of the relocating franchise soon after, making six more Pro Bowls as a Chief and leading Kansas City to two AFL crowns and Super Bowl IV. Dawson led the AFL in TD passes four times, returned from injury in 1969 to help give the AFL a 2-2 record in Super Bowls and Hank Stram mic'd-up immortality. The Hall of Famer quarterbacked the Chiefs for 14 years.
Warner probably had six quality seasons; those slates went so well he's a Hall of Famer. After his oft-mentioned stay in the Arena League and at Hy-Vee, Warner signed a Rams reserve/futures deal in 1997 and threw 11 passes in 1998. From 1999-2001: three Pro Bowls, two MVPs and a Super Bowl MVP. But Warner resurfacing after five years off the radar cemented this as an all-time career. Being cast as Matt Leinart's backup/tutor, Warner displaced the underwhelming first-rounder and in 2008 had a flawed '08 Cards team inches away from a Super Bowl title. He threw 16 TD passes in his first five Cardinal playoff games.
Morphing from an inconsistent San Diegan into the game's all-time passing kingpin in New Orleans, Brees is one of the defining 21st-century NFLers. The Dolphins were iffy on Brees' shoulder during a high-stakes 2006 free agency battle with the Saints. His six-year, $60M deal — the first of many Brees-Saints accords — changed the fortunes of one of the NFL's worst franchises. Brees gave the Saints a Super Bowl championship, made 13 Pro Bowls in black and gold, broke both marquee career passing records on "Monday Night Football" and secured first-ballot Hall of Fame entry. Pretty good.
The Steelers jettisoned Unitas a few years before they traded Dawson. This one stung worse, with Unitas still ranking high among the game's all-time greats. The Colts took a flier on the former ninth-round pick out in 1956, signing Unitas to a one-year, $7,000 contract (which was even less player-friendly than it sounds). Johnny U took the Baltimore reins full-time a year later, made the next 11 Pro Bowls and became his era's premier passer. Unitas led the Colts to back-to-back NFL titles — the first in "The Greatest Game Ever Played" — in 1958-59 and retired with 41 more TD passes (290) than the next-closest quarterback.