Lonnie Chisenhall was called up after posting solid numbers at AAA. He is worth a pickup if you need 3B help.
Marc Krauss was called up by the Astros and could hold some decent value moving forward if he can find enough playing time. He was performing very well as an outfielder at AAA. I doubt he will hit for much average but he can provide some power. For those on OBP leagues, he typically takes plenty of walks and posts high OBP's.
J.A. Happ should be back in the Jays rotation after the all-star break.
Brett Lawrie could return before the all-star break and hopefully he, being fully healthy, can improve on his disappointing statistics thus far. He is batting .209 for the season.
Jose Reyes should return next week but is coming back from an ankle injury and might not steal bases at the rate that we're used to for a while.
Brandon Morrow is still probably a few weeks from returning despite apparently having no structural damage in his arm.
Chris Perez should return next week but might not close immediately because he's struggled on his rehab assignment thus far.
Asdrubal Cabrera will likely be back before the all-star break.
Brian Roberts should be able to return around the all-star break and if you feel like gambling that he will stay healthy and need the 2B or MI help then he's worth owning.
David Price and Alex Cobb should each be back within a couple weeks. Price is going to make his first rehab start today and Cobb's concussion and ear-fluid symptoms figure to be cleared up soon enough but there's no guarantee on that. It's possible that Price will only make two rehab starts and he is a prime trade candidate right now because he should be able to dramatically lower his 5.24 ERA the rest of the way.
Clay Buchholz will probably be back next week.
Kevin Youkilis underwent back surgery and could miss the rest of the season.
Mark Teixeira could potentially undergo season-ending wrist surgery if his hitting and pain in the wrist don't improve when he starts swinging again.
The Mariners closing situation is a mess. It's anyone's guess who will get the most saves between now and the end of the season. I would rank the candidates as Tom Wilhelmsen, Carter Capps, Yoervis Medina, and Oliver Perez. All are worth owning if you are desperate and/or speculating on saves. I think Wilhelmson is their best option and should be fine in the long-run but it's also very possible that if Capps get a true shot he will run away with the role.
Nick Castellanos is worth a pickup right now in all AL-only or really deep mixed leagues. He should be called up very soon. Check out my write-up from earlier in the week here: http://www.faketeams.com/2013/6/17/4437986/has-anything-changed-nick-castellanos
Joe Blanton is an example of why using advanced statistics to try to determine whether a pitcher has been lucky or not and predict future ERA performance doesn't always work. His xFIP's from 2010-2013 have been 3.87, 3.15, 3.39, and 3.67, respectively. His ERA's from 2010-2013 have been 4.82, 5.01, 4.71, 5.62, respectively. Blanton's HR/FB%'s and BABIP's have been above league average in all four seasons.
Erik Bedard has allowed 2 earned runs or less 7 of his last 8 starts. He's worth a look when he has a favorable matchup.
With John Danks' velocity down I don't think he is worth starting right now. He has been struggling through even favorable matchups. If you take out his gem against the A's then his ERA on the year is 6+.