The top prospect in baseball is on his way to the majors, again. The Dodgers are calling up shortstop Corey Seager, who was named the best prospect in baseball on the mid-season lists from Baseball America, Baseball Prospectus, ESPN’s Keith Law, and SB Nation’s John Sickels. Already this season we have seen Kris Bryant (BA’s, Law’s and Sickels’s top preseason prospect), Byron Buxton (BP's and MLB.com’s top preseason prospect), Carlos Correa (the top pick in the 2012 draft), Addison Russell, Francisco Lindor, Noah Syndergaard, Miguel Sano, Carlos Rodon, Joey Gallo, Jon Gray, Archie Bradley, Alex Meyer, Blake Swihart and numerous other blue-chip prospects make their debuts. Seager, a 21-year-old shortstop who ranked fifth on BA’s list even before those others graduated to the majors, is notable even among that group.
The 18th overall pick in the 2012 draft and the younger brother of Mariners third baseman and 2014 All-Star Kyle Seager, Corey Seager was selected out of a North Carolina high school and made his professional debut at 18. He has hit .306/.368/.523 over parts of four minor league seasons since, making 356 of his 377 starts over that span at shortstop, and that line represents the level of production that is ultimately expected of him at the major league level. He won’t have that level of impact right away, of course, but he should see enough playing time down the stretch to justify his promotion. Incumbent shortstop Jimmy Rollins has been an offensive liability this year (.222/.276/.358, 75 OPS+), backup Kiké Hernandez is on the disabled list and third baseman Justin Turner was hit on the left pinkie by a pitch on Wednesday night (Seager started 19 games at third base in the minors this year).
In fact, if Seager proves viable in the field—where he reportedly has good hands and a strong arm but limited range—I wouldn’t be surprised to see him usurp Rollins as the team’s primary shortstop down the stretch, pushing the veteran into a defensive caddy role into the postseason. With Seager and fellow 21-year-old Jose Peraza now on the active roster, the 36-year-old Rollins, who has been a replacement-level player this year, may be no better than the third-best shortstop on the team’s active roster. He was also arguably no better than Hernandez, a 23-year-old–multi-position weapon with a career 122 OPS+ who suffered a hamstring strain on Sunday.
Whatever Seager’s role on the team over the remainder of the season, however, the implication of his callup is clear: He will be starting on the left side of the Dodgers' infield in 2016, be it at shortstop or third base. In fact, with Rollins, the injured Howie Kendrick and waiver-trade addition Chase Utley all due to become free agents in November, the Dodgers could have an all-rookie–double-play combination next April, with Seager at shortstop and Peraza, a top-50 prospect in his own right on those midseason lists, at second base.
Still, as exciting as Seager’s promotion might be for baseball fans of all stripes (save perhaps the Giants’ orange and black), we must temper our expectations. As productive as Seager is expected to be in his prime, he has hit just .276/.331/.450 since a late April promotion to Triple A in the hitter-friendly Pacific Coast League. He has hit for a more power of late, posting a .294/.333/.541 line over his last 19 games dating back to Aug. 16, but he doesn’t arrive in the majors as a player who was destroying Triple A pitching and is about to be unleashed on the National League. Rather, he arrives as a supremely talented youngster with a bright future who could very well improve both the Dodgers’ roster and lineup in the short term. What we’ll see from Seager over the remainder of the season is more likely to be a preview of his potential rather than the realization of it.