BIS: Why swap Figgins and Lopez?

The Mariners front office threw their fans for a loop on the first team workout of the spring when second baseman Jose Lopez trotted out to third base while newly-acquired third baseman Chone Figgins positioned himself at second. As Dave Cameron noted on this blog, “More and more, teams are realizing that if you can play a quality third base, you probably have the skills to transition to second, and vice versa.” But if it doesn’t matter who’s playing where, why bother?

Fast forward to the first week of the season: Rajai Davis hit a sharp ground ball off Doug Fister that sped toward the 3B/SS hole. Lopez, playing in on the grass with the chance of a bunt from the speedy Davis, dove to his left but missed the ball by inches. I couldn’t help but think to myself, “I’d bet that Adrian Beltre or Chone Figgins would have come up with that ball, and Lopez just cost them a base hit.” Before I could finish the thought, shortstop Jack Wilson flew into the picture, backhanded the ball, set his feet and launched a rocket to first, just in time to get Davis. Wilson bailed out Lopez, Fister, and the Mariners on a play that Figgins might have made (had he been playing third).

Sure, it’s just one play, but this example illustrates that playing two good fielders on the left side of the infield could cause some overlap, effectively making the total less than the sum of the parts. On some ground balls, both the third baseman and the shortstop could make the play, but only one needs to.

I created a model of the Mariners’ infield using each player’s 2009 performance. I’ll spare you the long explanation for now (I’m running over my word count as it is), but I projected the distribution of ground balls allowed by Mariner pitching in 2009 onto their projected infield before and after the swap. Since I didn’t have a model for Lopez and Figgins at their new positions, I used average third basemen (Melvin Mora, Kevin Kouzmanoff) and above-average second basemen (Dustin Pedroia, Chase Utley, Aaron Hill) as proxies at their respective positions.

For example, let’s compare the Mora/Wilson/Pedroia/Casey Kotchman infield to Figgins/Wilson/Lopez/Kotchman. Adding up the full season of plays, the drop-off at third was significant, but Jack Wilson reached most of the grounders anyway. In fact, Mora (Lopez’s proxy at third base) covers an estimated 58 fewer plays than Figgins, but Wilson’s elite defense makes up 45 of those from shortstop! Add in the 18-play increase from Lopez to Pedroia (Figgins' proxy) at second base, and it’s a net gain of five plays for the team. Using similar infield proxies at third and second, the Mariners’ improvement ranges from zero to 15 plays per season as a result of the swap. Even though it’s not a huge improvement, every run could make a difference in the competitive AL West.

Regardless of the reasons, the (very) early returns on the position swap are positive: Figgins has saved one run at second according to Baseball Info Solutions, while Jose Lopez has accumulated eight Runs Saved, leading all third basemen. So far, so good in Seattle.