Was biggest trade-deadline mistake a deal that wasn’t made?

Daniel Mengden began this season with a 2.91 ERA in his first 12 starts with a .606 OPS against. In case you don’t know, Mengden plays for the A’s. Also, those results look similar to what Zack Wheeler has produced over the last 11 starts — 3.20 ERA with a .589 OPS against. Mengden followed…