In my collection of college range factors, Mitchell Haniger was the 2nd highest rated outfielder (behind Mariners' speedster Michael Faulkner) out of 36 (Auburn's Ryan Tella had a higher rating in centerfield). The Brewers drafted him 38th overall out of Cal Poly (he was drafted by the Mets in the 31st round out of high school in 2009). He would only play 14 games with the Brewers after signing, but it was in Class A and 12 of the games were in centerfield. Fangraphs rated him as the 13th best prospect in the Brewers system, citing not only his good range in center, but his strong arm and as a possible 5 tool player. However, many have shown some doubts about his speed, questioning how long it will stick with him and whether or not it is elite. Despite the great range he showed in college, there is some talk that he might move to right-field if his speed diminishes, where his strong arm would still play (and where he played earlier in his college career). It does seem that he gets good jumps and reads, at least he did when I saw him.
In watching him, you notice he has good size, but isn't bulky. It is an ideal size for a centerfielder with some power. He seems to have a powerful swing, and I don't think the bat speed is slow, but it seems to get a little long at times, and according to other scouting reports, there seems to be some worry that he will swing and miss a lot. That said, he walked more than he struck out in his junior year of college, suggesting he has a good approach. You can find a good breakdown of his swing here. He starts out with an open stance, but like most hitters (especially right-handers) he closes it when the ball gets there.
It seemed that he was having a little bit of problems with up and in balls when I watched him on Milb.TV, which you would expect from someone with a long swing. Overall, his mechanics are really noisy and he has a lot of moving parts
to his swing. I am much more skeptical of him hitting for average than
the scouting report above, at least soon. The patience he showed though
makes him seem like he could be a low average/good on-base guy though,
but I didn't see the power that was reported.
Haniger is a high draft pick out of college that should traditionally move fast. However, there are plenty of questions regarding nearly every aspect of his game. If he is unable to stick in center, he loses a lot of value, but the data and the eye test say that unless he just loses a lot of speed (and he is not a "bad body" player, he shouldn't regress speed wise more than you would expect a normal player to),he should stick in center. I question whether or not his bat will play against advanced pitching, unless he makes some mechanical tweaks. He has good patience and discipline, so perhaps that will come around. If it does, expect Haniger to have a very successful professional career.