Skewed Left: The Billy Beane Famous-Old-DH Gambit

Kevin Mitchell was 36 years old and coming off 84 games played in three years when he signed with the Oakland A’s in the middle of spring training 1998. A former National League MVP and home run and RBI champion from across the Bay Bridge, Mitchell was clearly on the way down from his 1989-90 mini-peak and mini-resurgence with the 1993 and 1994 Reds, but first-year general manager Billy Beane made the call for Mitchell as part-time DH.

It was Beane’s first platoon as general manager. He would switch off the right-handed-hitting Mitchell with the young(er) lefty hitter Matt Stairs.

It didn’t work at all. Despite getting a majority of his at-bats and more than 80 percent of his starts against left-handed pitching, Mitchell just couldn’t hit anymore. He followed up his .157/.275/.373 in limited action the year before with a .228/.279/.346 in 136 plate appearances with Oakland. He was released in August and never played again.

But in addition to being the reigning platooner-in-chief’s first foray into that world, Mitchell represents another first that keeps on coming up. He was Beane’s first old and declining DH.

Between that spring training signing and the Adam Dunn trade this week, the A’s have turned this into an art form. They aren’t the leaders in quantity of old DH’s during Beane’s tenure—that would be the Yankees, pretty much no matter how you set the minimums of age and plate appearances. But for a low-budget team that would never think to acquire most of these players as free agents in their prime, Oakland has certainly cornered the market on corner men and DH’s of great accomplishment several years prior.

All of these guys were as old or older than Dunn’s current age of 34 when Beane acquired—or re-acquired—them. None hung around for more than one year—or in Frank Thomas’ case, two separate stints, neither longer than one year.

• Frank Thomas, age 38/40 (2006/2008) – 448 career home runs when acquired by the A’s for the first time, 516 the second time.
• Mike Piazza, 38 (2007) – 419 career home runs when acquired
• Jason Giambi, 38 (2009) – 396 home runs
• David Justice, 36 (2002) – 294 home runs
• Eric Karros, 36 (2004) – 282 home runs
• Nomar Garciaparra, 35 (2009) – 226 home runs
• Mike Sweeney, 34 (2008) – 197 home runs
• Hideki Matsui, 37 (2011) – 173 MLB home runs and 505 between MLB and the Central League

Just like it was for Mitchell, Oakland was the end of the line for five of those eight players—Thomas, Piazza, Justice, Karros and Garciaparra. It will be for Dunn as well, assuming he stays true to his word to reporters that this is probably all there is. (He would be the youngest retiree ever from the 400-home run club.)

Dunn’s A’s career began with a powerful statement that he’s not quite done. After hitting .201/.321/.410 in the first 3 ½ years of his four-year deal with the White Sox—a .732 OPS that’s a departure from an extremely consistent .902 OPS with his first three teams—Dunn did this to Chris Young in his A’s debut.

Whether or not the A’s made the acquisition expecting improvement, Dunn should be a nice improvement to a banged up and suddenly offensively limited lineup. Still, Dunn can’t tail off much from his .281 TAv from the 2014 White Sox and still provide much of anything in the way of positive value, given his defensive and baserunning nonexistence and liability, respectively.

Of Beane’s old DH’s, the results are pretty mixed. Counting Thomas twice, four of the nine seasons mentioned above saw the player improve his true average from his previous season or team. Five went the other way, including three who you could legitimately say collapsed, losing 39 or more points of TAv when going to the A’s.

The factors should work both ways on this. Obviously, these are all players on the undesirable slope of their aging curve. However, there are some factors that should be helping these players both show improvement and actually improve. One is a potential selection effect—that for the A’s to sign a slugger, he probably has to be coming off a subpar season, at least for him, and there could be some bounceback there.

The other gets to the first point with Mitchell. The A’s will generally be giving less playing time to that DH than his previous team did when the player was a year younger; especially with the A’s lately, that often takes the form of a platoon.

It’s been particularly noticeable with the right-handed hitters, some of whom have seen the percentage of their plate appearances with the platoon advantage see a spike.

With lefties like Dunn, that hasn’t always been so easy. Dunn was already being platooned by the White Sox, so the percentage isn’t going to go up much from 86 percent of plate appearances with the platoon advantage. But if the A’s can keep that up, he should have a good chance to be productive.

Against Mariners lefty James Paxton on Tuesday, Bob Melvin started Derek Norris at designated hitter, Geovany Soto at catcher and lefty-killer Nate Freiman at first (not that we’d ever come out in favor of Dunn at first).

And given that Dunn has a significant career-long platoon split that’s only growing, Billy Beane’s favorite move of acquiring the platoon-able player as well as an old standby of signing the old DH for one last shot might help get the Donkey into the playoffs for the first time.

Thanks to the Baseball-Reference.com Play Index for research assistance.