Mariners select top outfield prospect Julio Rodriguez, Alberto Rodriguez, Ray Kerr

The Mariners announced Thursday that they’ve selected the contract of top outfield prospect Julio Rodriguez, thus adding him to the 40-man roster and protecting him from the 2021 Rule 5 Draft. Also added to the 40-man roster were fellow outfielder Alberto Rodriguez and lefty Ray Kerr. Seattle’s 40-man roster is now up to a total of 39 players.

Rodriguez was about the most obvious 40-man addition any team would make in advance of Friday afternoon’s deadline to protect players from the Rule 5 Draft. The 20-year-old is heralded as a potential superstar, ranking as the sport’s No. 2 overall prospect at Baseball America and MLB.com and landing No. 6 over at FanGraphs.

Despite his youth, Rodriguez is expected to make his big-league debut at some point in 2022 — if not on Opening Day then perhaps early in the year. (The looming collective bargaining talks could impact the timing.) Rodriguez, 21 in late December, split the 2021 season between Class-A Advanced and Double-A, turning in a dominant .347/.441/.560 against much older and more experienced pitching (particularly in Double-A). The Mariners are expected to be aggressive in free agency and in trades this winter as they look to launch themselves back into the postseason, but president of baseball operations has already stated there’s “no scenario” where Rodriguez or the other very best prospects in his system are traded (link via The Athletic’s Corey Brock).

As for Alberto Rodriguez, the Mariners picked up from the Blue Jays in the 2020 trade that sent Taijuan Walker to Toronto. About nine months older than Julio, Alberto split the 2021 season between Class-A and Class-A Advanced, hitting at a .289/.379/.470 clip with 10 home runs, 31 doubles, five triples and 15 steals. The 21-year-old’s best skill is his considerable raw power, per scouting reports at BA, MLB.com and FanGraphs, though there are concerns about his hit tool and defense in the outfield corners. The elder Rodriguez generally ranks in the No. 20-25 range on Mariners prospects lists, although Seattle has arguably the best farm system in baseball, so he’d place higher with most other teams.

Kerr, 27, joined the Mariners as an undrafted free agent in 2017 and has steadily risen through the system. After working as a starter early in his pro career, the 6-foot-3 lefty moved to the bullpen in 2021 and notched a combined 3.18 ERA with a huge 36.8% strikeout rate, a slightly high but manageable 9.8% walk rate, and a strong 53% ground-ball rate. A hard-throwing southpaw who can touch the upper 90s, miss bats and keep the ball on the ground at that rate in Double-A/Triple-A would surely have piqued the interest of other clubs. The Mariners’ selection of Kerr immediately thrusts him into the mix for a bullpen spot next season — particularly given the lack of proven southpaws in the relief mix at present.