My bold prediction is 3 years, $13 million.
If it were my baseball team, I'd appoint Riske co-closer along with Turnbow, unless some really good offer came along in which we could get a young-ish closer. As it is, I'd bet Melvin will keep looking for a trade for someone like Chad Cordero, which would make the bullpen surprisingly strong, moving D-Bow potentially as far back as the 7th inning.
Also, I'd like to make this the official David Riske pun thread. I'm sure I'm not the only one who needs to get a bunch of really bad jokes out of my system.