Cubs are better with Kendall?
It's hard to know what to make of this deal until we know what cash considerations were involved, but my guess is the A's are essentially responsible for most of the (approximately) $3 million the A's owe Kendall for the rest of this season (the Pirates owe him a nice chunk, too, but I'm guessing they're not getting any relief in this deal).
Basically, the A's are simply getting rid of a headache. They've now scored three or fewer runs in 10 straight games, which they hadn't done in nearly 30 years. Somebody had to go, and apparently the hitting coach wasn't available.