He was quite productive during the NCAA spring season, hitting .311/.443/.633 with 15 homers, 28 walks, and 38 strikeouts in 177 at-bats for the Volunteers. Drafted in the supplemental first round, 34th overall, by the Detroit Tigers, Stewart remained just as productive against professional pitching, hitting .285/.380/.508 in his first 256 pro at-bats. 185 of those at-bats came in the full-season Low-A Midwest League, where he ran up a .286/.380/.492 line for the West Michigan Whitecaps. Remember that the Midwest League is a pro-pitching environment; in relative terms this was excellent production with a 153 wRC+.
Stewart is a 6-0, 205 pound left-handed hitter and right-handed thrower, born December 10, 1993. His best physical tool (as you'd expect with these numbers) is power, but he is not just a brute-force masher. He has some feel for the strike zone and while most of his home runs are pulled, he can go straightaway or to left field often enough to keep the defense honest.
College scouting reports indicated that he handled both fastballs and breaking balls without much trouble, and so far pro pitching hasn't been a huge challenge to that history. We'll have to see if that holds true when he gets to Double-A. He did show a pronounced platoon split (.908 OPS against right-handers, just .740 against lefties) and he'll have to work on that.
Although his bat was one of the most potent available in the 2015 class, questions about his glove kept him out of the regular first round. His arm and speed fit best in left field and he doesn't have great defensive instincts. If he loses too much speed as he ages he could wind up at first base, which would put additional pressure on his offense of course.
While there are still some questions to answer as he moves up, Stewart's pro debut was an overall success. Heading into 2016, he's at least a Grade B- prospect.