Why in the world would we make a move to get Sanchez back on the team? Guy is a bum.
There are other bums in the bullpen who have hurt the team more from the bullpen than he will from the bench. The team's been without a backup shortstop for weeks, and they have no way to improve infield defense in late innings if they want to. He solves both. He's not the best use of a roster spot in the world, but there are worse ones.
His ideal role is as an insurance policy who barely plays. For example, it allows you to more freely use both Parra and Kendrick/Adams as pinch hitters, because Sanchez backs up the entire infield and makes things less risky.