SAN DIEGO—Texas Christian lefthander Matt Purke is an enigma. Baseball America's 2010 Freshman of the Year (and an unsigned 2009 first-round pick), the draft-eligible sophomore entered this season as one of the consensus top three prospects for the 2011 draft, but his stock slipped a bit in the season's first half, and his outing at San Diego State on Saturday raised more concerns for scouts.

Purke got off to a strong start, racking up five strikeouts through two scoreless innings, using a sharp slider as the putaway pitch for four of them. His fastball sat at 90-91 mph those first two innings, topping out at 92-93, but his stuff dropped off precipitously in the third, when the Aztecs scratched out an unearned run. A scout commented in the third that Purke's arm slot dropped noticeably, and his stuff flattened out. He sat about 88 that inning, then dropped into the 84-86 range in the fourth inning. He exited after allowing a leadoff single in the fifth (when he threw fastballs at 82 and 85 mph), having thrown 79 pitches. He did not strike another batter out after the second, and he finished with three walks, four hits and two runs (one earned).

For most of last year, Purke worked in the 91-94 range and held his velocity deep into games. A scout who saw him two weeks ago said his velocity was OK, so this week's dip is troubling.

"We're trying to figure it out. It's just a dead arm deal," TCU coach Jim Schlossnagle said. "Last week he touched a couple 96s early in the game, and he was rolling, then he gets in the sixth inning and all of a sudden he just loses his feel for it . . . And he's such a team guy, he's such a team guy, to where he'll say, 'Coach, I'm fine, I'm good to go 75 pitches.' He's doing everything he can, he's the biggest team guy in this dugout. So we all feel for him. It's going to be better, we think. Everybody and their mother's looked at his arm, there's nothing we can find in terms of any kind of injury. It's just he'll feel great for a while, and then all of a sudden it'll go away."

Purke did flash some plus sliders early in the game, when the pitch mostly sat at 77-78 mph. It became slurvy after the first two innings, dropping into the 73-76 range. Schlossnagle said he also throws a curveball, especially against righthanded hitters, but it was hard to tell his breaking balls apart Saturday. He mixed in a few changeups at 77-78, using one to get SDSU cleanup man Chris Wilson to pop out to second base with a runner on third in the third inning.

Purke always competes—that much is undeniable. He buckled down with men in scoring position in the third and fourth innings to minimize the damage of Aztec rallies, and the Horned Frogs went on to an easy 8-2 win. For all the gnashing of teeth about Purke's season, he's 4-1, 1.55 with 47 strikeouts and 15 walks in 41 innings, though he has allowed 10 unearned runs. Opponents are hitting just .192 against him.

"To me it's good news. It's not good news that he's not pitching the way he's capable, but it is good news that the best Matt Purke is still to come," Schlossnagle said. "I will say this: Everybody remembers Matt Purke last year as the guy who pitched lights-out in (the Mountain West Conference) tournament, lights-out in a regional, lights-out in a super regional, lights-out in Omaha. Nobody remembers he pitched most of the season with about a 3.50 ERA. His numbers are actually better (this year). In terms of the pitcher he needs to be for our team, his numbers are better. And I'm not making light of the situation, but that tells you how competitive he is. I think he'll eventually be fine, but we're all trying to find it right now for him."

Schlossnagle also points out that Purke has not really worked his way into midseason form yet. He took last summer and fall off, then entered the spring behind schedule. A nasty blister on his finger early this spring set him back another two weeks, because he could not even play catch for about 10 days, Schlossnagle said. He's also "had some back stiffness here or there," Schlossnagle said.

But the fact is, this is an extremely strong draft class, and Purke is getting passed on draft boards by players with fewer question marks.

"His stock has fallen some," a National League scouting director said a week and a half ago. "I think going into this year, you would have said he'd be one of the top three players off the board, and I think the other two lefthanders (Danny Hultzen and Jed Bradley) have moved ahead of him, at least in my eyes. He still shows you the plus fastball and plus slider, it's just not as often. Not every breaking ball will be plus, but last year three out of four sliders were plus, now it's one out of three. So you'll get a plus one, an average one and a well below-average one.

"For sure, he can't command his fastball to his glove side, get it inside to righthanded hitters. Now they can look away, he'll go backdoor with the breaking ball or arm side with the fastball. The arm action and the delivery, I think, hinders his ability to command it. The arm slot is even a little lower than it used to be, but the delivery is really stiff front side, very upright, and obviously, one leads to the other. For a lefthander to get the ball in to righthanded hitters, he has to get through his front side and finish, and his body won't allow his arm to get there, not to mention the slot."

Even scouts with big-picture reservations about Purke's delivery or fastball command still agree that he's a premium talent with serious upside and great makeup. But this week, scouts were left to scratch their heads and wonder: What's wrong with Purke?