How good is Rays rookie outfielder Mikie Mahtook?

2015 was an unusual season for Tampa Bay Rays outfield prospect Mikie Mahtook. He spent the season bouncing between the major league roster and the Durham Bulls in the Triple-A International League. Mahtook really didn't have much to prove in Triple-A; he played well there in 2014 (.292/.368/.458, wRC+125) but available at-bats in Tampa were scarce.

Although he hit a home run in his first major league at-bat back in April, the roster shuffling seemed to get to him on some level and his 2015 sojourn in Durham brought less-than-stellar results: he hit just .249/.304/.366 in 385 at-bats for the Bulls this season, well off last season's pace. He did steal 10 bases in 11 attempts but his isolated power was down some 50 points compared to last season and his strike zone judgment slipped.

The Rays brought Mahtook to the major leagues in September and gave him some playing time. He needed to make a good impression to keep himself in the picture for 2016. He did just that, hitting .353/.397/.706 with six homers this month. All told he finished .295/.351/.619 in 105 major league at-bats, hitting nine homers. WAR likes the early return on his outfield defense and overall he rang up 1.8 fWAR in those 105 at-bats.

Okay, so which is the real Mahtook, the guy who scuffled in the IL, or the guy who clobbered major league pitching in September?

Let's start by looking at what we wrote about him back in April, since the background is still valid.

Mahtook should be familiar to college baseball fans: he was a star for three seasons at Louisiana State University. . .Heading into the 2011 draft season he was viewed as a certain early pick, although not everyone agreed he should go in the first round. Although his college numbers were excellent and he thrived against top competition, there were mixed opinions about his physical tools. Some doubted that his power would translate to higher levels. Some felt that he didn't run quite well enough to play center field but didn't show enough pure power for a corner. Some said that these concerns were overblown and that he was actually a very good athlete with under-rated physical tools to go with his obvious baseball skills,

He did end up in the first round, going at the end of it to the Rays with the 31st overall slot.

As a professional Mahtook has provided uneven results. On the positive side, his outfield defense has turned out to be quite good; he has no problems managing center field and has also played well in both left and right fields. His instincts are sound and his arm is accurate, if average in strength. His running speed is a tick above average but he's developed into a solid base-stealer with a 75% success rate in his career thus far. Again, that is a matter of instincts and polish and he has those.

The questions focus on his offense. His plate discipline is inconsistent and he's had trouble making contact at times, although part of that could be deliberate in relation to attempts to hit for more power. He whiffed more than once a game in Triple-A last year although it was also his most productive season as a pro: . .Mahtook's makeup and work ethic are considered excellent; if anything, observers say he sometimes tries too hard and gets down on himself if things don't go well. Time will tell if that is a real problem or not, but trying too hard is certainly better than not trying hard enough.

Mahtook will need to improve that platoon split to last as a regular. If not, his other skills (defense, baserunning, occasional power) will still make him a viable fourth outfielder.

The up-and-down nature of his 2015 performance fits the pre-season narrative very well. International League observers seemed to think that Mahtook was discouraged and/or pressing too much during his second go around the circuit and was getting away from what makes him successful.

He responded with a positive flurry when he got playing time in September. Of course, we are talking about a small number of at-bats and one hot month of major league play. Even during his big league tear his BB/K/PA ratio was unattractive.

He hit .294/.368/.667 against lefties and .297/.316/.541 against right-handers in the majors, so on the surface the platoon split problems that hampered him in the minors were not apparent in the Show. But look beneath the surface: his walk rate was 6.5% against lefties with a 26% K-rate. That's not too hot. But against right-handers it was even worse with 2.6% walks and 28.9% strikeouts. That's, um, really not good.

When the pitchers get a better look at him, especially right-handers, they will make adjustments and he'll have to adjust back. It remains an open question how Mahtook would perform over a larger sample.

For all this doubt, I like him as a player and have since college. Even with the erratic hitting he has a broad set of skills that should make him a viable role player. Mahtook is better than he played for Durham this year, but he's not going to post a .970 OPS over a full major league season.