Thursday June 19th was the lowest scoring day of the season in terms of runs per game, with a minimum of ten games played. Only the Toronto at New York game, which the Yankees won 6-4, produced more than the major league average of runs yesterday. The dozen games averaged 5.33 runs per game. The only day lower was March 30th, opening night, with one game that produced four runs.

The interesting thing to me is that it was a put the ball in play day. There were just 6.87 K per 9 IP, and 2.61 BB per 9 IP. That’s the 8th lowest strikeout day and 12th lowest walk day. Only a dozen balls left the yard, so either batters were making weak contact, or fielders were simply gobbling up balls in play.

What’s causing this weak contact? Has the group of pitchers as a whole developed a new pitch? My first thought was, maybe everyone is starting to throw a cutter. According to FanGraphs, the percentage of cutters thrown grew in recent years, although I’m not sure how much of that is recording the pitch better versus actual use. Still, given the success of Mariano Rivera with the pitch, adding one to the arsenal as an out pitch would make a lot of sense. The point of the pitch is that the late movement moves the ball off the sweet spot, which could lead to more balls in play and fewer hits than expected.

Maybe someone with more access to PITCHf/x data can look at Thursday’s games and see how many outs were on cutters? Or if cutters are being used in out pitch situations more than in previous years?

Update: Jeff Zimmerman, who writes at Fangraphs.com and Baseballheatmaps.com, sent my the percentage of cutters thrown each day of the season according to PITCHf/x. Thursday saw one of the lowest uses of cutters this season, just 3.4%. So much for that theory.