Every MLB playoff contender's biggest weakness

Arizona probably got worse at the trade deadline when it traded ace Zack Greinke, but the team did add two formidable starters in Zac Gallen and Mike Leake. Still, the staff has been an issue since the Diamondbacks lost Luke Weaver, who still doesn't have a clear return date. The bullpen has also become an issue lately with Greg Holland getting demoted from the closer role and the pen sporting a 4.53 ERA overall.

Mike Soroka has been a true ace for Atlanta this season, and Dallas Keuchel has fared well despite signing in June. After that pair of groundball pitchers, the rotation has been inconsistent. Max Fried has an ERA above 4.00, and Julio Teheran's ERA metrics show that his 3.46 ERA could be a ticking time bomb. The hope is that last year's ace, Mike Foltynewicz, is able to rebound after returning from the minors recently.

Boston has two former Cy Young winners and Chris Sale on its staff, so starting pitching didn't look like an issue coming into the year. Unfortunately, the Red Sox starters rank 20th with a 5.07 ERA, and Rick Porcello (5.74 ERA) and Sale (4.68 ERA) have been particularly disappointing. A recent eight-game losing streak could have effectively ended Boston's playoff chances, and its starting pitching has been the biggest issue.

It's no mystery that the Cubs lineup has struggled against southpaws this season, ranking 20th with a .740 OPS. They remedied the issue at the trade deadline by acquiring Nicholas Castellanos, and the eventual return of Ben Zobrist could also help. Still, a potential playoff matchup vs. the Dodgers left-handed-heavy starting rotation could be a nightmare.

Cleveland fixed a lot of its hitting issues by acquiring Yasiel Puig and Franmil Reyes at the trade deadline, and Jose Ramirez's surge since the All-Star break has also helped. However, the bottom of the lineup still has its share of issues, with Jason Kipnis' .724 OPS and Robert Perez coming back to earth since the break. Those are potential easy outs that AL teams like the Yankees, Astros, and Twins don't have when they're healthy.

Houston made the surprise move of the deadline when it acquired Zack Greinke, giving the team a fearsome trio of starters that also includes Justin Verlander and Gerrit Cole. Before that point, the Astros had major issues at the back end of their rotation, and that could be an issue again if something happens to the big three or No. 4 starter, Wade Miley.

While the Dodgers bullpen has a respectable 4.04 ERA, ranked eighth in MLB, Kenley Jansen hasn't been his usual dominant self, and free agent signing Joe Kelly has been a major disappointment. L.A. didn't make any major moves at the trade deadline but seems likely to shift Kenta Maeda to the pen for the third straight year. He should be able to help, but Jansen showing consistency will be critical.

It's been a rough few weeks for the Brewers, losing Brandon Woodruff, Jhoulys Chacin, Gio Gonzalez and Zach Davies to injuries. The result has been a pitching staff in shambles. While the Brewers expect all of their pitchers to be healthy before the playoffs, it could be too little, too late for their postseason hopes.

Minnesota acquired Sam Dyson at the trade deadline, only for the right-hander to struggle and go on the IL with a shoulder issue. Taylor Rogers has been spectacular as the closer lately, and Sergio Romo has also helped, but much of the heroics at the bottom of the bullpen have been smoke and mirrors. The Twins rank 14th in bullpen ERA (4.43), as some of their relievers have regressed recently.

The Mets apparently felt they had a viable shot at the NL wild card, acquiring Marcus Stroman at the deadline and keeping Noah Syndergaard and Zack Wheeler. They now have one of baseball's most talented starting rotations, but the bullpen is still a huge issue. The team's 5.17 ERA in the pen ranks third-worst, and closer Edwin Diaz has been shaky, to say the least.

The Yankees have done a remarkable job surviving major injuries this season, but their starting rotation remains a major concern for the playoffs. Luis Severino's status is still up in the air, and the rotation ranks 17th in baseball with a 4.73 ERA. While Domingo German has been a savior for the team, New York needs a better final stretch from Masahiro Tanaka, James Paxton and J.A. Happ as the team gets ready for the playoffs.

Oakland continues to withstand some big blows, led by breakout pitcher Frankie Montas' 80-game PEDs suspension. While the club is in a good position in the AL wild card race, as a small market team it doesn't have the depth of some of the other AL playoff teams like Houston and the Yankees. An injury to center fielder Ramon Laureano has already exposed the team's outfield depth, and A's fans should similarly have their fingers crossed that Matt Chapman, Matt Olson and Marcus Semien are able to go down the stretch unscathed.

Philadelphia's starting rotation looked thin entering the year, and it's become a much bigger issue as the season has progressed. While Aaron Nola has pitched well, Jake Arrieta is battling through an elbow injury and the rest of the rotation has been under almost constant change. The result is a 4.50 ERA overall, just 15th in MLB. The bullpen has also become a surprise problem due to numerous injuries, including to Seranthony Dominguez, David Robertson and Pat Neshek.

The Giants got back into the NL wild-card hunt with a great July, as they continue to search for hitting. The team's .704 OPS ranks fourth-worst in MLB, but there is reason to be optimistic with recent surges from Buster Posey and Mike Yastrzemski. The team also acquired Scooter Gennett at the trade deadline, but the recent injury to breakout outfielder Alex Dickerson was a huge setback.

The Cardinals lineup has finally started to deliver on its promise due in large part to Paul Goldschmidt's hot streak. The return of Marcell Ozuna gives the team two elite hitters, but there are major issues behind them. St. Louis lacks another hitter with an .800 OPS, and the team particularly had issues at third base and center field. While the Cardinals have talent, their hitting performance hasn't stacked up with the elite NL teams.

The Rays pitching has been outstanding this season, but the depth has been tested. Tyler Glasnow suffered an arm injury earlier in the year, and more recently Blake Snell, Jose Alvarado and Yonny Chirinos went down with injuries. An area that has been a strength this year has started to become an issue more recently.

Washington has the worst bullpen ERA in baseball. The Nationals added three relievers at the deadline and signed Fernando Rodney earlier this season, but it still might not be enough to fix the severe issues bridging innings between their outstanding starters and closer Sean Doolittle.