Red Sox sign Joel Pineiro. As a CLOSER??!!??

The Red Sox have signed perennial Mariners' spare Joel Pineiro to a one-year, $4 million contract. The shocking part is the contract apparently has incentives tied to closing games.

Joel Pineiro has never looked good against anyone other than the Rangers. Here's a guy who doesn't top 90 mph except when the wind is blowing hard, and has a tough time around the corners. How is he a CLOSER?

I know Theo Epstein is way smarter than I am, so there must be something I don't know.