Brandon McCarthy - McCarthy was #1 on my Buy Low list even before Saturday's excellent outing against the Padres, as the 30 year old is showing his typically excellent control to go along with the 2nd-highest swinging strike% of his career as a starter, a much-improved GB rate, and the best velocity of his career by far. I believe that he can offer back-end starter value in all formats going forward.
Derek Dietrich - Dietrich has cooled off a bit of late, but he's still hitting 250/373/446 through 56 ABs. He's pretty awful in the field, so he isn't going to get as much latitude as a lot of guys, but Dietrich has made some pretty positive strides at the plate in the early going. He has good power for a middle infielder (and for a 24 year old), and he's cut his chase rate in half this year, resulting in a much better walk rate and an improved swinging strike%. His 29% LD rate has somehow only resulted in a BABIP of .263....if he keeps hitting like this the AVG is going to be a help rather than a hindrance. All in all, Dietrich looks like a potential 12-team league starter at 2B, and I'd definitely want to have him rostered in most formats at the very least.
Alfredo Simon - Simon wasn't nearly as impressive Sunday as he has been for much of the season, but he managed his 6th straight quality start in a 4-3 win over the Brewers. Simon scuffled with his control and couldn't miss any bats Sunday, but he still managed to hold Milwaukee to 3 runs on 5 hits and 1 walk over 7 innings on the strength of 14 ground-ball outs. Simon is more like a 4.00 ERA pitcher than a 2.00 one, but his swinging strike% has been solid despite the low K rate, and his GB rate has been strong as well. He's been solid enough that I'd probably have him on my roster in most formats, but each start has been a bit tougher for him of late, and the upcoming schedule (COL, @PHI, STL) is difficult enough that I'd have a hard time relying on him in the near-term.
Luis Valbuena - Valbuena is definitely just keeping 3B warm this year for one of the kids, but I'll stubbornly reiterate the fact that he's a solid 3B option in OBP-based formats. Valbuena doubled and tripled Sunday to bring his line up to 227/378/379 on the year, and the best contact rate of his career coupled with a 32% LD rate are being torpedoed by a BABIP of just .279. Valbuena could easily hit .250-.260 if he keeps going the way he has been, and with a bit of pop and a passel of walks mixed in, he's not a bad option at all in deeper leagues.
Jason Hammel - Hammel tossed his sixth straight quality start Sunday against the Cardinals, allowing 3 runs on 7 hits and 2 walks over 6 innings, striking out 5. Hammel is enjoying his first non-Rockie venture into the NL, posting the best swinging strike% of his career along with vastly improved control. Good fortune with BABIP has allowed Hammel to post an ERA a good run and a half lower than it probably should be thus far, but he could still offer back-end starter value even after some likely regression. He has the Braves on the road for his next outing along with a late-May start against the Padres in SD, so he could be a fairly reasonable streaming option this month in all formats.