Jonny Venters is a walking, talking anomaly. And it isn't just because he spells his first name funny. In two years pitching out of the bullpen for the Atlanta Braves, Venters has allowed 410 ball hit in play (not including bunts). In those 410 balls in play, 290 have been hit on the ground. Being a worm that lives in the infield of Turner Field has to be a terrifying prospect. Venters leads the majors in ground balls percentage over the past two years at 70.5 percent. His teammate, Peter Moylan, is second at 69.2 percent. Nobody else is even close.
In simplistic terms, the trajectory of a batted ball can affect a batter's success. There are a lot more factors as a comment by Robbie Knopf on another recent post correctly suggests. The speed of the ball off the bat makes a difference too. What is counted as a line drive can be just as much a soft hump-backer to the shortstop as it can be a rope into the gap. But in general and simplistic terms, it's pretty hard to hit a ground ball into a homer. Perhaps an inside the park homer is possible, but if a batter hits the ball on the ground, it isn't going to go over the fence.
A ground ball has to be fielded of course. And that is often out of the pitcher's hands. But if you induce ground balls, good things can happen. They've happened a lot for Jonny Venters. The Braves have leaned on him heavily. He led all relievers in appearances in 2011 with 85. The year before, Venters pitched in 79 games. The Braves were criticized at the end of 2011 for burning out the bullpen, but when you have the likes of Venters, Moylan, Kimbrel and O'Flaherty at your disposal, it must be a hard temptation to resist. And Venters has been amazingly reliable in his first two years in the majors.
Venters' numbers are eye-popping. In his two years, his ERA has been 1.95 and 1.84 respectively. He's given up only three homers in 171 innings of work for an astounding 0.2 homers per nine inning rate. He's only given up six hits per nine innings and was even stingier in that category in 2011 with a 5.4 rate. Venters has fanned batters at a 9.9 per nine inning clip for his short career. His only statistic that is a detriment is his 82 walks, good for a 4.3 walks per nine rate. He's also hit 13 batters, so his control could be better. His walks are one reason for his FIP to come in at 2.74 or +.85 for his career. But geez, you'll take that from a reliever, right? Especially when 22 of his 206 base runners have been erased with double plays.
But there is more. While the high ground ball rate limits fly balls, Jonny Venters also does a great job of limiting line drives. Batters against him only delivered a 13.7 percent line drive rate against him in 2011 and his career rate is 14.4 percent in that category. League average during that time span is 18.7 percent. Venters' WPA was an excellent 4.28 which means he shared a good part of win probability for the Braves whenever he pitched. Is Venters' low BABIP rate for his career of .264 a product of his lack of line drives and large numbers of ground balls or just luck? It would easy to argue the former.
If 70.5 percent of Venters' balls allowed in play result in a .221 batting average against and a .245 slugging percentage, that means that eight out of ten batters against him are going to lead to good results (the other one being a strikeout). Indeed, Venters has been favored by a .530 OPS against for his career. Amazing.
While it remains to be seen how the stress of all those appearances will work against Venters in the long run, what we've seen from him in his two years in the majors has been remarkable. If he can withstand the high usage and continue getting pitch values of 12 runs above average on his fastball and 11.9 runs above average on his slider, we can continue to expect a bunch of worms to be traumatized for years to come.