When Justin Smoak was acquired, he arrived with lofty expectations. He was a top draft pick, a highly regarded prospect, and a projected middle of the order bat. His performance rarely lived up to the billing, but it's still a testament to how poorly he's hit that, less than two and a half years after the trade, Smoak has essentially played himself out of a job.
Smoak has clearly been unimpressive this season. He's posting a .189/.258/.312 slash line, good for a 58 wRC+. Much has been made about Brendan Ryan's miserable campaign at the plate, but Ryan actually has a higher batting average (.195), on-base percentage (.284), and wRC+ (60) than Smoak. And needless to say, what is tolerable for a slick fielding shortstop is much less so from an average first basemen. For Smoak though, the problems run far past this season.
In over 1,300 career plate appearances, Smoak is a .214/.296/.359 hitter (80 wRC+). There are just twelve first basemen since 1950 to post a lower career batting line (minimum 1,000 PA's) and only one (Dalton Jones) was allowed to reach 2,000 plate appearances. Moreover, Smoak doesn't have a redeeming split: he hits poorly at home and on the road, and he doesn't fare well against lefties or righties. He doesn't walk often enough to ever post a robust OBP and I can't remember the last time Smoak really put a charge into a ball. Teams tend not to have long leashes with first basemen that can't hit, and given Smoak's dreadful season and recent demotion, the M's appear to have lost patience.
With all of that in mind, I think it's time to stop giving Smoak regular plate appearances. If they want to let him pinch hit while starting once or twice a week, fine. But with only twenty-one games left in the season, the Mariners would be best served letting Alex Liddi and Mike Carp platoon at first.
Carp does have a reverse platoon split, but that appears to be tied to some extreme BABIP variation, not a rare ability to hit left handed pitching. In any case, he's handled righties adequately in his career (104 wRC+) with no drop off in power. He's not a great bet to become a regular first basemen, but perhaps a strong finish can help him work into a platoon role.
Liddi hasn't accrued enough playing time for me to make sweeping judgments about his skills, but thus far in his big league career, it's clear that he has fared much better when facing southpaws. Liddi has walked in about ten percent of his at-bats against lefties, with a slightly better contact rate and more power than when facing a fellow right-hander. Liddi has looked overwhelmed at times by big league pitching, so using him exclusively against lefties might be a good way to ease him back into the league.
At this point, the Mariners are just playing out the string. There aren't a whole lot of games remaining on the docket and they should be using whatever time is left to evaluate the roster for the 2013 season. Unfortunately for Smoak, the M's are probably at the point where he isn't in their long term plans anymore. Liddi and Carp are hardly stars, but it's worthwhile to give the pair more at-bats against big league pitching to see if either can stick at this level. Sadly, it's a plan that aligns better with the Mariners future than letting Smoak play every day.