Marco Estrada will pitch in a minor league game tomorrow and should be back within a couple weeks. His 5.32 ERA this year compared to 3.64 ERA last season can mostly be explained by his HR/FB% going from 10.5% to 15.7%.
Ryan Braun may be out of action until the 1st or 2nd week of July. If you own him then it is a worthwhile tradeoff. He should come back at 100% if he's out that long.
Chris Carpenter is going to start throwing again. Although he's a long-shot to join the Cardinals rotation at some point and have extended success there if you have a really deep bench or a lot of DL spots then he's worth a pickup just in case.
Aaron Hill should return next week. Eric Chavez will likely be back in a couple weeks. This could be bad for Martin Prado owners. Eric Chavez might get most of the starts at 3B against RHP while Hill should start almost every day at 2B.
Matt Kemp should be back by next weekend but Carl Crawford could be out until the all-star break. In any case, once the Dodgers have Kemp, Crawford, Andre Ethier, and Yasiel Puig all healthy they will have to bench one of them each day because it's extremely doubtful that Puig will be sent back down at any point.
Angel Pagan re-injured his hamstring and could be out until early August if he needs surgery.
Chad Gaudin might be okay to pitch Tuesday vs. the Dodgers. If he can't make the start it's likely that the team will have to call someone up to take his place because they don't have an off-day this week so they cannot move their entire rotation up a day.
Lucas Duda may be placed on the DL with an oblique injury. If he is then Ike Davis has a shot to be called back up. Davis has 4 HR in his last 2 games and is hitting .361 with a 1.294 OPS in his last 10 games. He should be called up soon enough regardless of whether Duda is placed on the DL. I still remain confident in Davis to be valuable for fantasy the rest of the way once he's back.
Jon Niese has been placed on the DL with a left shoulder injury and it's likely that he will need season-ending surgery if his shoulder doesn't begin to heal on its own in the next few weeks.
Bryce Harper should be able to return on or around July 1st.
Wilson Ramos is set to return around the all-star break if he doesn't have any more setbacks with his hamstring.
Jedd Gyorko should return sometime next week.
Mike Adams will miss at least a couple weeks with a biceps injury. It's notable because if Jon Papelbon is traded while Adams is on the DL then you'll need to look for other alternatives as far as who will replace Papelbon as the Phillies closer. Antonio Bastardo might get a shot in that scenario.
Jeanmar Gomez will return to start Wednesday vs. the Mariners. He'll face off against Felix Hernandez. I would not play him in this particular matchup but he could have some spot-start value in NL-only leagues the rest of the way.
Chris Heisey will return early next week. He should end up sharing playing time with Xavier Paul in left-field at first but if Heisey gets hot he'll likely play every day and be worth a pickup in NL-only and deep mixed leagues.
The Mets traded for Eric Young Jr. and he's been starting in center-field and hitting lead-off since they acquired him. I really like his potential to stick there the rest of the way and post a solid SB total.
B.J. Upton is looking like himself again this month. He's hitting .238 with 4 HR, 3 SB, and an .828 OPS. His K rate is down and his walk rate is up in June compared to his first two months. He's worth buying low on through a trade or picking up if he's a free agent in your league.
Jordy Mercer is now the Pirates starting shortstop and can provide a decent average with moderate power and speed. He's worth a pickup if you need a SS or MI, especially in an NL-only league. He's also eligible at 2B in most formats.
D.J. LeMahieu has produced very well as the starting second baseman for the Rockies. He has 9 SB on the year in just 33 games and is hitting for decent average. He just hit a HR today as well. I picked him up two days ago in an NL-only league so he still might be available in your league right now but not for long.