I like to snoop around the minor league stat pages and look for prospects that are putting up solid or interesting numbers but aren't getting much attention. Obviously guys like Kingham and Glasnow are having huge breakout seasons and Polanco is the man, but who are some under-the-radar players showing solid development that could eventually turn into solid MLB contributors? Here are a few so far.
Jason Creasy: Evoking the arcane mysteries of the cosmos, Creasy is a "projectable right handed pitcher", drafted in the 8th round in 2011. He's taken a big step forward this year, surpassing his strikeout total from last year in just over half the innings, with fewer walks. He's doing this in relief and he's had some issues with HR's, but a young pitcher with potential having success is encouraging.
Ryan Hafner: After posting decent but uninspiring numbers at SC in 2011, Hafner had a well-publicized meltdown last year, walking 68 batters in 60 innings. This year, he's putting up similar numbers to Tyler Glasnow. There are the obvious caveats that he's 2 years older than Glasnow and pitching in relief, but this is still a very positive development. WTM notes on PP that he was throwing 89-92 with a promising new slider in camp, whereas he pitched in the upper 80's with no secondary offerings when drafted.
Brandon Cumpton: Last year in AA, Cumpton looked like the next Jared Hughes: didn't strike out many, didn't walk many, didn't let up many HR's. That's not the sort of pitcher that's likely to be a real contributor in the majors. He had a brutal 2 starts in Altoona this year, then was promoted to Indy as a fill in. As was the case with Phil Irwin last year, he was abducted by aliens during the trip who gave him a robotic arm. In 41 IP, he's put up the best K/9, GO/AO, and FIP of his career. If he keeps it up (big if), you have to put him in the mix for spot starter/back of the rotation starter. He might be less of a blow-up risk than Oliver, just because he can throw strikes.
Kyle Haynes: Haynes has very quietly put together 47 innings of solid relief. It's hard to know what to make of him, since he has the rare "good changeup in A ball" and he's being used as a reliever, but he's pitched better than, say, Nate Baker ever has, a trait that worked out for Phil Irwin at least.
Quinton Miller: As the initial high school RHP project, it's hard to believe Miller is a) still in the system and b) only 23. After years of 5+ ERA's and poor peripherals, he finally started showing signs of life, getting 18 K's in 14 IP in Bradenton. He's pitched 5.2 solid innings in Altoona since, and could be a relief option going forward.
Max Moroff: Moroff was drafted last year out of high school and plays short, although he's not a sure bet to stick there. His overall line of .215/.335/.348 is okay, but his peripherals (27/25 K/BB, .133 ISO in 165 PA's) are pretty outstanding for a guy who's young for the league and plays a premium position. He's got a .245 BABIP, and while hitters have more control over that than pitchers, there's no reason to think he's a low BABIP guy as he had a .386 last year. Moroff could turn some heads if his BABIP regresses to .300.
Josh Bell: Bell is hardly under the radar, but his month so far in May is notable in that after a pretty bad start to his career, his plate discipline finally showed up. Over his first 174 plate appearances, he struck out 28% and walked 4% of the time. It's a small sample, but so far in May, he's striking out 16% and walking 20% of the time. He's doing other good things too, like hitting for power.
Jacob Stallings: Stallings is probably more of a fringe prospect than most of these guys, but he's a defense-first catcher who has seen a drop in K% (from 28% to 21%) a power surge (.102 to .175 ISO), and maintained a 12% BB rate all while skipping over A ball. If he can keep these gains, he's at least in the conversation as a MLB backup and still has time to be more than that.