Andy Pettitte, SP, Yankees: He must have kept himself in pretty fine shape during his brief retirement because the five starts back in New York have been terrific (three wins, 2.78 ERA, 1.01 WHIP). Plus control is no surprise (just seven walks), but Pettitte is also putting people away (32 strikeouts). The pickoff move remains lethal as ever. His next two turns are against the Mets and Nationals - good teams, but not offenses to fear.
Ryan Dempster, SP, Cubs: The 1-3 record is a joke given how well Dempster has pitched (2.59 ERA, 1.08 WHIP); obviously the Cubs have hung him out to dry on several occasions. But Dempster's luck has turned somewhat in his last two turns - Chicago has scored 18 runs for him - and there's a strong chance he'll be moved to a contending club at some point in July. No one can be this unlucky for six months, right? Dempster could easily win 10-12 games the rest of the way, even if he pitches a little worse than his current level.
Brandon Beachy, SP, Braves: The glittering ERA and WHIP jump off the page (1.87 and 0.95, respectively), and he's also spiked the strikeouts of late. But what type of season-long workload will the Braves expose Beachy to? It's not that we're expecting a shutdown at some absurdly-early point, but just keep in mind this young arm has never been exposed to 150 innings in a season (Beachy was a reliever when he entered pro ball). Even if he's not sent to the showers prematurely, a stat give-back in August and September is highly likely. Quietly see if anyone in your league needs a pitcher and is willing to overzealously chase what Beachy has already posted; he's good, but he's not this good.
Derek Lowe, SP, Indians: While some unlucky chaps like Cliff Lee can't buy a win, there's Lowe with his fortunate seven victories and 3.06 ERA. The ERA is as much a fluke as the wins are; Lowe averages only 2.7 strikeouts per nine innings, his strikeout and walk rates are almost even, and his WHIP is a toxic 1.46. His extreme ground-ball profile helps to some extent, but a 78.3 strand rate is mostly just good fortune. If you mash the peripherals and try to estimate Lowe's ERA, you get something in the high 3s or low 4s. A major correction is coming, it's just a matter of when.
Tom Wilhelmsen, RP, Mariners: The general blueprint looks stacked against Wilhelmsen, at least as far as a closing gig goes. The Mariners would like Brandon League back in the big chair at some point (so they can try to trade him), and fresh-recall Stephen Pryor arrived with the "stopper of the future" tag attached. That established, Wilhelmsen has a win and a save over the last two Seattle wins, and he's looked the part in the late innings, striking out 36 men (against a reasonable nine walks) over 30 innings. Sometimes the smartest way to handle jumbled bullpens from a fantasy standpoint is simply to follow the momentum and the recent assignments; most modern managers are reluctant to change anything that's been working.
Felix Doubront, SP, Red Sox: Pitchers are basically guilty-until-proven-innocent in the jagged AL East, where four of the five parks are dangerous to work in and every team has a capable offense. But Boston's surprising lefty has acquitted himself nicely through the opening third of the year, posting a 3.75 ERA and 1.35 WHIP along with six wins and a zesty strikeout rate (66 punchouts in 62.1 innings). Doubront has been one of the surprise stars for AL-only players this year, and his profile is also relevant for medium and deep mixed leagues.
Francisco Liriano, SP, Twins: He's given us two terrific turns since rejoining the rotation (12 IP, 7 H, 1 R, 3 BB, 17 K) and a reasonable matchup is on the way (at home against Philadelphia). Just make sure you don't get tied to any long-term commitment with Liriano - the messy mechanics (and crooked numbers) can return at any time, without warning. It seems like a folly to put him in the sell list - if you're in a smart league, no one is likely to trade for him - so all you can really do is give him a shot to pitch for you, but on the shortest leash possible.