David Robertson, if you didn't pay attention, had a remarkable season. While pitching to a 1.08 ERA (410 ERA+), he racked up exactly 100 strikeouts in 66.2 innings pitched. That equates to 13.5 K/9. Not only is that the highest in Yankee history (minimum of 50 IP), but it's the best in American League history. That's right. In 111 years (spanning more than 10,000 individual seasons), no pitcher has struck out batters at a better rate.*
The last Yankee reliever to strikeout more than 100 batters in a season was none other than Mariano Rivera, who did so in his epic 1996 campaign. He became the closer the following season and the rest is history. Of course, he walked one fewer batter than D-Rob despite tossing 41 more innings. D-Rob's been able to get away with a relatively high walk rate because of his ridiculous K-rate... imagine if he could cut down on the walks just a little. Wow.
Anyway, if 2012 is Rivera's last year, would you want D-Rob to replace him? Vote.
* What's amazing is that a starter is second on the list: Pedro Martinez' 1999 season, in which he K'ed 313 batters in 213.1 IP (13.2 K/9).