Top prep and juco prospects in Arizona

Scottsdale Community College left-hander Stephen Tarpley was on the radar two years ago as a senior at Gilbert (Ariz.) HS, but a knee injury wiped out most of his senior spring, and questions about signability led him to slide in the draft to the eighth round, where Cleveland took him but didn't sign him. After a year at USC where he pitched well, Tarpley transferred back home to junior college and could slide into the top three rounds in this year's draft, which is very light in the left-handed college arms department.

Tarpley was 89-93 on Tuesday, not quite where his velocity was earlier in the spring but still plenty for a left-hander, and he showed some feel for his curveball and changeup, although both pitches were wildly inconsistent, ranging in quality from 35 to 55 (on the 20-80 scouting scale).

He pushes his changeup out, so it rides up and away from right-handed batters too often, but when he finishes it properly, it has some slight fade and he can get it over the plate. Similarly, when he stays on top of the curveball, it has depth and angle, but he gets on the side and overthrows it so it comes out like a bad slider.

His arm is quick but he makes no use of his lower half, so despite an athletic build he's barely scratching the surface of what he might be able to do. He drifts off the rubber almost immediately, takes a moderate stride, but doesn't have his pitching hand ready when his front leg lands and raises his back elbow higher than you'd like to see.

Tarpley left USC after his freshman year under a cloud of rumors, mostly surrounding his off-field makeup, that will likely cause him to go later in the draft than his raw ability would indicate. The fact that his delivery often looks lazy, like he's just playing catch rather than making an effort to finish all of his pitches out front, is more glaring because of the makeup concerns. Perhaps cleaning up his delivery will be about more than just teaching him to rotate his hips and lengthen his stride.

He's about a third-round talent, maybe late second, if we set all of that aside.

• Gilbert HS shortstop Dustin Peterson, younger brother of New Mexico third baseman DJ Peterson, may be the best draft prospect in his family this year, as he has a looser, leaner body than DJ does and could potentially stay in the middle infield, albeit at second base rather than at short.

He has a very simple swing, with a direct path to the ball and good hip rotation to drive the ball out to the gaps. During the game I saw, however, he seemed to have trouble picking up spin, and even swung and missed on a fastball up, the kind of pitch an advanced high school hitter doesn't usually miss. Peterson won't stay at short in pro ball, more likely moving to third although I don't see any reason he couldn't handle second base.

• Desert Ridge (Ariz.) HS shortstop Riley Unroe is also getting some increased attention of late, with rumors that he'll go as high as the second round. Son of former big league infielder Tim Unroe, Riley made the rounds at the showcases last summer but has swung the bat better this spring and showed more athleticism than he did last summer.

Unroe, a switch-hitter, loads his back elbow very high, so he has to yank his arm down to get his hands into hitting position, but after that he has a very rotational swing and solid plate coverage, with a smoother swing from the right side that keeps him more upright through contact.

Like Peterson, he'll probably move off shortstop to second or third base. I'd have him more in the third round than the second, but I wouldn't be surprised to see a team that believes in his bat -- and he has performed well in the last few weeks, when he's been scouted the most -- take him somewhere in the top 75 picks.

• Basha (Ariz.) HS shortstop Jamie Westbrook is something of a scouts' favorite out here because he plays all-out, all the time, and gets far more out of his physical tools than most players would. He's hit for a lot of power in his high school career thanks to a max-effort uphill swing where his entire back side collapses and he tries to jerk everything out to left field -- an approach that has worked so far but isn't going to carry over to the next level.

He's maybe 5-foot-8 and doesn't have the arm for anywhere but second base or left field. He's committed to Pepperdine and should be a very good college player, but I wouldn't turn him in as a draft prospect out of high school.