With the injury to Mariano Rivera, the New York Yankees will be looking to David Robertson as well as Rafael Soriano to close games.
Robertson has been lights out this season. His strikeout rate leads the league at 46.7%, and his K/9 of 15.75 is third behind Jonny Venters' 17.42 and Jason Grilli's 16.36.
Robertson's chase rate is up from 25.0% in 2011 to 32.0% so far in 2012. His heat maps indicate that he's been hitting the edge of the strike zone more.
It looks like Robertson has avoided throwing in to righties so far this season, while also peppering that outside edge to lefties. That kind of control near the zone means hitters are forced to protect more. Borderline pitches are swung at more and this has lead to that big jump in his K-Rate.