A blip on the radar

We’ve grown accustomed to seeing David Robertson in the 93-94 mph range this year, more than 2 mph faster than he where he was at when he first came up in 2008.  In the 8th inning of yesterday’s game, he didn’t bring his velocity with him, averaging under 91 mph for the first time all year:

In Saturday’s one-run game, Joe Girardi opted to use Rafael Soriano in the 8th instead of Robertson, a technique he has not employed much this summer.  Is Robertson fatigued?  Injured?  Was Friday just an anomaly?  We’ll see.