So far he has been extremely lucky, at least it's good for his confidence.
In the 7 games that he has pitched for us (July 27 - Aug 8) he has 0 ERA with 5.74 xFIP.
His BABIP is .158.
Just for argument sake, since Grilli came over (June 1st) he has 1.99 ERA with 2.66 xFIP, .225 BABIP in 22.2 innings.
I guess sometimes it's better to be lucky than good...