Even though Jake Arrieta fell a little short in his quest to get his 20th win last week, he remains one of the more intriguing ace pitchers in all of Major League Baseball and their respective MLB betting fans. Last month, he threw his first career no-hitter for the Chicago Cubs as he continues to build a case for winning the Cy Young Award in the National League.
An Inside Look at the MLB Betting Report on Chicago Cubs’ Jake Arrieta
— Chicago Cubs (@Cubs) September 17, 2015
He has a 1.99 ERA and the league’s third highest wins above replacement (WAR), a metric that compares how many wins a player contributes to his team in comparison to an average player from that league. However, the way he became an ace is what makes him an interesting story.
In 2013, Arrieta was toiling along as about a replacement level player. Playing for the Baltimore Orioles and then the Cubs, he had had mostly an average career. However, just making it to the major leagues was seen as an accomplishment for a fifth-round draft pick. His ERA over the first four years of his career never got below 4.66.
While the numbers didn’t seem to be changing – and weren’t that great – his mechanics were changing. The release point where a pitcher sends the ball home is a crucial characteristic. A pitcher with a high release point has to put more of a downward plane on the pitch, making it sink as it goes through the zone. Release points far to one side or the other lead to more horizontal movement through the zone.
Most pitchers feature a fairly constant release point, thanks to mechanics that the pitchers learn as kids. However, Arrieta’s release point kept going up and moving toward the third-base side of the pitching rubber. Over time, his release point has gone up about six inches and moved horizontally along the rubber by about twice that much.
Normally, if a pitcher’s release point changes, he is still growing. In Arrieta’s case, because he had stopped growing, this means that his mechanics had to change. New release points mean new arm angles – which influence the way a pitcher performs against batters who are left- and right-handed. A sideways arm angle can be confusing to same-handed hitters – which is one reason why pitchers tend to perform better against same-handed batters than they do to opposite-handed batters.
Before 2013, this described Arrieta’s situation. However, once his release point started moving upward, he started reversing that trend. So he’s getting more consistent as well – and retiring batters he didn’t before. Arrieta’s movement of his release point is quite rare. In any one year, a typical pitcher only experiences a standard deviation in their release point of about an inch.
In Arrieta’s case, between 2009 and 2015, Arrieta is in the 95th percentile. Between 2011 and 2015, only eight MLB pitchers saw as much movement in their release point as Arrieta did. With those changes came big improvement – and a major change in Arrieta’s fortunes in MLB.