In the final game against Seattle last week, Detroit was batting in the 7th inning. They had just scored two runs to take a one run lead, and had runners at first and third with one out. Jim Leyland had Hernan Perez pinch run for Victor Martinez at third, as a sacrifice fly or slow infield ground ball could provide an insurance run. Andy Dirks was due up, having pinch hit for Matt Tuiasosopo leading off the sixth inning. Charlie Furbush, a lefty, was pitching. Dirks has a career .265 / .328 / .392 slash line against lefties. Leyland could have pinch hit for Dirks, as he did for Tui, but he did not. Dirks struck out and Perez was stranded at third.
In Saturday night's historic comeback against the White sox, Andy Dirks again pinch hit for Tui. He hit a three run home run off of the right-handed Nate Jones.
Jhonny Peralta is working out in the instructional league, preparing to return for the final three games and likely the playoffs. Since Peralta was suspended, the Tigers have played 47 games. They have used a right-handed pinch hitter twelve times in meaningful situations.
For Andy Dirks: Matt Tuiasosopo twice, Torii Hunter twice, Ramon Santiago once, and Austin Jackson once.
For Alex Avila: Nick Castellanos and Brayan Pena each once.
For Don Kelly: Nick Castellanos and Torii Hunter each once.
When a right-handed pinch hitter was needed against the Mets with the pitcher due to bat, Brayan Pena and Tui were each used once.
Torii Hunter and Austin Jackson will be starting in the playoffs as long as they are healthy, so the options for a right-handed pinch hitter that Jim Leyland is willing to use are Tui, Santiago, Castellanos, and Pena. If Don Kelly is starting, the Tigers have larger issues. So the key question is "Who can pinch hit for Andy Dirks or Alex Avila against a LOOGY?".
Matt Tuiasosopo has 218 career plate appearances against left-handed pitchers, resulting in a .199 / .294 / .351 triple-slash line. He can "run into one", but beyond the occasional walk and home run offers little.
Ramon Santiago has 578 plate appearances against lefties, resulting in .231 / .295 / .326. He is Tuiasosopo without the power.
Brayan Pena has 427 plate appearances resulting in .251 / .285 / .328. He is Santiago without the walks, and no better than Alex Avila's .215 / .309 / .327 career line against southpaws.
Nick Castellanos had 125 plate appearances in AAA against lefties in 2013, resulting in .299 / .392 / .411. But will he even make the postseason roster?
Meanwhile Jhonny Peralta hit .347 / .400 / .556 against lefties this year, and .262 / .339 / .449 for his career.
It is not even close; Peralta is by far the best option to hit against a LOOGY. Andy Dirks does not have much of a platoon split with a career line of .265 / .328 / .392 against lefties. Without Peralta on the roster, the Tigers may actually be better off in the playoffs never pinch hitting for any of the left-handed hitters.