What is Going on With Jason Grilli?

Jason Grilli has been one of the top middle relievers in all of baseball so far this season, netting a 1.80/2.33/2.16 ERA/FIP/xFIP along with 0.5 wins out of the bullpen in exactly 20 innings. Currently, Grilli has the highest strikeout rate of his career, by far, at 42.7%.

The huge jump in strikeout rate would immediately make one believe a big regression is due for Grilli, who has a career rate of just 18.6%. However, when you look deeper at his numbers, his performance looks a bit more sustainable. Most notably, Grilli has seen his velocity increase significantly, and he has turned into a strict two-pitch pitcher. His fastball velocity is now up to 93.4 miles per hour, up from his career average of 92.7mph and 92.4 last year. Along with that, his fastballs thrown percentage is up to 64.9% compared to a 60.8% career average and his slider percentage is up to 33.2% from 28.8% for his career. An increase in velocity from a 35-year-old reliever like this is certainly rare, but it has been the key catalyst to

While a strikeout rate as high as Grilli’s is probably unsustainable, expecting him to drop to the 7.34 K/9 rate that he has maintained for his career is unlikely if he continues to throw with this level of velocity. With the Pirates playing a lot of tight games due to a strong pitching staff and weak offense, Grilli is being put into some strong roles. He already has nine shutdowns, just four off his career high of 13 posted in 2007 with the Tigers.

Although he has had an odd career, it seems as though Grilli has finally found a role in which he excels at. He is near the league lead in holds at 12, just behind league leaders Joel Peralta and Vinnie Pestano who both have 13. In holds leagues, Grilli looks like a guy who should be targeted for many reasons. If he is not already on a team, a waiver wire pick up should certainly help in a number of categories. If he is owned, it probably would not take much to pry him from that owner’s hands. The owner will likely be looking to sell high on Grilli, but his performance looks somewhat sustainable so the price you pay for him may end up equaling his performance, as long as you don’t go and offer something crazy for him.

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Ben has been at RotoGraphs since 2012 and focuses most of his fantasy baseball attention toward dynasty and keeper leagues.

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I doubt there will ever be enough cases to do a proper study on it, but I wonder if older players’ elbows are better able to handle a sudden velocity spike than younger ones. Naysayers were anecdotally right about the much younger Duffy.