Josh Satin for Ike Davis makes sense. It's a simple move. There isn't much to say about it.
Collin Cowgill for Mike Baxter is a little confusing. Baxter did not really do much to warrant a demotion. His batting average was only .212, it was in limited playing time and his OBP was over .100 points higher. He was one of the team's best pinch-hitters and actually provided reliable defense in the outfield. Cowgill could perform similarly but I don't see the purpose of this move.
Now, Josh Edgin for Rob Carson is a move in its own league. Carson has been brutal this season. He seemingly gives up a home run every time he shows up on the mound. But I really don't believe Edgin is going to be an improvement. When Edgin was first sent down he went to AA Binghamton and pitched to the tune of a 7.88 ERA. Things were only marginally better in Vegas where he posted a 5.91 ERA. I understand that they want to replace Carson with another lefty, but they weren't comfortable using Carson and they likely won't be very comfortable with Edgin. Justin Hampson is a lefty who has posted a 2.16 ERA against lefties this season and a 1.54 ERA in his last 10 games.
Josh Edgin was the first move of the season that signified the Mets may actually use the minors to turn players around. However, bringing Edgin back up when he has basically shown no improvement diminishes the authority of these moves. If Edgin didn't actually have to earn his way back, will Davis and Carson?
I feel for Davis and Carson, two talented players who just seemingly lost it this season. I feel for Baxter who didn't really do anything wrong but is a victim of this slide.
Hopefully the Mets will find the players that optimize this lineup and team. I'm just not convinced these moves will do that.