Sean Forman is the creator of Baseball-Reference.com, an online baseball encyclopedia of players, teams and box scores in the major and minor leagues.
Yankees shortstop Derek Jeter is struggling through what is easily the worst hitting stretch of his career. For the 100 games from June 21 of last year to April 13 of this year, Jeter has hit .257 with just a .662 O.P.S. Sabermetricians often combine a player’s on-base percentage and slugging percentage as a quick proxy for batting performance. This is well below the current American League average of .712 for all batters and .691 for shortstops. Before his current slump, dating to May 2010, the worst O.P.S. of his career over 100 games was .699 from July 24, 2003, to May 25, 2004, which he rebounded from with an .823 O.P.S. in 2004.
Given Jeter’s age (he will turn 37 in June) and the severity of his slump, what are the prospects that he can pull out of it? From 1947 to 2011 there have been 28 middle infielders, including Jeter, with careers similar to his: with above-average O.P.S.’s and at least 5,000 plate appearances before their age 37 season.
This group ranges in ability from the light-hitting Tony Fernandez and Bobby Avila to the strong-hitting Barry Larkin and Joe Morgan. Even in this group, Jeter stands out. He leads these star middle infielders in hits and batting average, trails only Cal Ripken Jr. in plate appearances, Jeff Kent in O.P.S., and, if you include the postseason, has a wide lead in total games played at shortstop.
But what does this group do on the other side of 36? Middle infielders as a group take far more abuse while in the field than outfielders or corner infielders, and as a result tend to age more quickly. For example, Roberto Alomar, whose numbers bear a strong resemblance to Jeter’s, had his last good season at age 33 and was out of baseball at age 37.
From our previous group of 26 star middle infielders (excluding the currently active Jeter and Miguel Tejada), only 14 even played past age 36, averaging three seasons among them. Several did play well at 37 or older. Lou Whitaker, Davey Lopes, Kent, Morgan and Fernandez all had multiple years when they hit better than the league average. At age 38 and playing third base, Ripken had a .952 O.P.S. in 86 games. But none of these top hitters were playing shortstop full time.
Only three full-time shortstops of the 26 played and stayed at shortstop past 36: Larkin, Alan Trammell and Pee Wee Reese. Jeter’s career arc has interestingly and probably coincidentally matched Reese’s and Trammell’s — an average year at age 34, a superlative year at age 35, and back to or below average at 36. The results would be dire if Jeter continued to match their careers. At age 37, Trammell continued to struggle with a .695 O.P.S. and finally retired in 1996 after posting a .526 O.P.S. in 66 games. Reese was worse, with a .667 at age 37 and a .555 at age 38 in 103 games.
Larkin is perhaps the best-case scenario. From ages 37 to 40, he averaged 93 games and a .719 O.P.S. Larkin’s usage may point the way for the Yankees. He was injured for two of the four seasons and played in only 45, 145, 70 and 111 games. He had a nearly league-average .771 O.P.S. at age 40 playing in 111 games as a part-time starter.
The Yankees may have taken Jeter’s durability for granted. Jeter is one of four players, along with Brooks Robinson, Bobby Abreu and Pete Rose, to play in 150 games in every season from age 30 to 36, and so far he has played all but two innings of the 2011 season.
Jeter may defy expectations and bounce back to be the best-hitting shortstop in the American League. It would be unprecedented, but Jeter has outlasted his competition and critics in the sabermetric community already. At the very least, the Yankees may want to find a shortstop who can spell Jeter for 30 to 40 games a season to make that rosy outcome more likely.