Luke Montz vs. John Jaso

By Jason Wojciechowski on May 7, 2013 at 9:12 AM

In the seventh inning last night, Derek Norris led off with a double to left-center (which he crushed, by the way), bringing the tying run to the plate. With lefty Nick Hagadone on the mound, Adam Rosales pinch-hit for Eric Sogard. After he flew out, Bob Melvin sent Luke Montz out to hit for John Jaso, which caused Tito Francona to relieve Hagadone with righty Bryan Shaw.

Given the relative merits of Jaso and Montz (as opposed to Rosales and Sogard), it seems likely that Melvin had the ball in his court: he could choose Jaso vs. the lefty or Montz vs. the righty. He was never going to get Montz vs. the lefty.

Because I wasn't sure about that choice at the time, and still wasn't sure when I woke up this morning, I thought I'd throw out some numbers so we know what Melvin was working with.

Here's Jaso v. LHP in his career: .176/.308/.237 in 162 plate appearances.

Here's Jaso v. RHP in his career: .269/.367/.415 in 984 plate appearances.

Jaso's not good against lefties. He was actually worse against them in 53 trips last year: .119/.250/.143. The best you can hope he'll do is eke out a walk.

Baseball Reference recently added minor-league splits back to 2008, though it does not appear that they are yet aggregated, so here is Montz year to year against lefties and righties:

2008 .260/.352/.496 (146) .266/.337/.426 (315)
2009 .216/.336/.388 (137) .162/.260/.270 (232)
2010 .186/.234/.279 (47) .210/.319/.320 (119)
2011 .351/.473/.667 (146) .242/.356/.445 (337)
2012 .248/.351/.608 (148) .208/.287/.437 (272)

There's no such thing as a sample size big enough to make me happy, but Montz has made his living the last two years, and in his career in general, roasting lefties. His performance against righties has sometimes been adequate and sometimes been awful—and remember that the 724 OPS he put up against righties last year came in the Pacific Coast League, a place not well known for its run-suppression.

There are other factors at work besides Montz and Jaso, of course, including how tired Hagadone was, how fresh Shaw was, how the two hitters match up against those two particular pitchers, not just as righties and lefties but as players with specific arsenals and sequencing routines, how Jaso and Montz were feeling that day, and, not least, the small possibility that Francona might lose his mind and leave Hagadone in to face Montz.

I don't have answers in any of these areas, and Melvin, even to the extent he had answers, didn't have an hour to sit around and think about it. So I don't know if he was right, but I do know he wasn't wrong.