When the Yankees signed Rafael Soriano to a three-year contract over the winter, they thought they had secured one of the game's most lethal set-up man/closer combos. With Soriano handing off to Mariano Rivera, teams scarcely had a chance if they trailed heading into the eighth inning.
As it turns out, New York does have a killer combo pitching in the late innings. But Soriano isn't a part of it. While the $35 million man missed nearly three months with an elbow injury and has a lousy 4.47 fielding independent ERA (FIP), David Robertson, a former 17th-round pick from Alabama snagged by the Yankees for $200,000, has been money.
The undersized righty with tree-trunk calves has the highest strikeout rate (13.7 batters per nine innings) among relievers this side of Kenley Jansen and Craig Kimbrel. With 2.4 Wins Above Replacement, Robertson ranks third among 'pen arms behind Kimbrel and Sean Marshall and has provided as much or more value than every other starting pitcher on the Yankees, save for CC Sabathia.
Robertson's wicked pitching has The New York Post's Joel Sherman comparing him to Rivera circa 1996, setting up for a top-notch stopper much like Mo once did for John Wetteland. Sherman also says that, "Robertson has pitched so well, in fact — with poise and dominance — that you wonder if we are watching Rivera’s heir apparent." And, as catcher Russell Martin notes, Robertson appears to have picked up a bat-cracking cutter:
Robertson, after a fit of early wildness, has found greater mastery of a cutter that Martin said, “is hard to explain because it has such good rotation it just explodes in the end.”
According to our pitch data, Robertson has thrown a cutter slightly less than a quarter of the time in 2011. Sitting at 92-93 mph, the cutter moves in on left-handed hitters (away from righties) about three inches more than his fastball. Here's a visual of Robertson's mix of pitches in terms of release velocity and pitch break. The cutters are the slightly brighter orange blotch in the upper left-hand quadrant, with the fastballs to the right and Robertson's big-breaking curve in blue in the lower left quadrant:
In Sherman's article, Martin says that Robertson and Rivera have similar stuff. He's on to something: Mo's cutter is a bit slower (averaging 91-92 mph), but it breaks in on lefties by the same amount as Robertson's. And while no one would dare compare Robertson's cutter to perhaps the most dominant pitch in baseball history, Robertson is getting excellent results with the cutter so far. Hitters are swinging and missing at Robertson's cutter 28 percent of the time (21 percent league average) and are slugging .220 against the pitch (.393 average).
At this rate, it seems like Rivera will be busting bats until he's AARP-eligible. But, with Robertson adding a cutter to his already-nasty fastball/curve combo, he makes for a fine closer's apprentice.