Peralta is the Brewers best trade piece other than Contreras on the MLB roster. I don't think either get traded and it would have to be a blow the Brewers away type of trade.
Rays trade 1:
Rays get: Peralta
Brewers get: C. Williams (SS), M. Montgomery (SP) and B. Taylor (3B)
Rays trade 2:
Rays get: Peralta
Brewers get: J. Caminero (3B) and M. Johnson (SP)
Orioles trade:
Orioles get: Peralta
Brewers get: C. Mayo (1B), C. Povich (SP), C. McDermott (SP) and J. Ortiz (SS)
Twins trade:
Twins get: Peralta
Brewers get: B. Lee (SS), D. Festa (SP) and C. Soto (SP)
Mets trade:
Mets get: Peralta
Brewers get: L. Acuna (SS), R. Mauricio (SS/2B), R. Clifford (OF) and C. Scott (SP).
There are not that many teams that could pull off a Peralta trade these were just a few that I could find. I don't think any of these trades are realistic. It will take a lot for Peralta to be traded and that list of teams that could afford or even have the prospect surplus value to trade for Peralta is really small.