Answer by taking a quote from the following article:

Patrick John Neshek (born September 4, 1980) is an American professional baseball pitcher for the Philadelphia Phillies of Major League Baseball (MLB). He previously played for the Minnesota Twins, San Diego Padres, Oakland Athletics, St. Louis Cardinals, Houston Astros, and Colorado Rockies. The Twins selected him in the sixth round of the 2002 MLB draft from Butler University. Neshek made his MLB debut for the Twins on July 7, 2006, and played for them until 2010, except 2009, which he missed due to Tommy John surgery.

Neshek has a very unorthodox style of delivery that transitions from starting at a submarine angle to finishing sidearm with an explosive thrusting motion. Near the release of the pitch, his torso and arm angle in a moderate "V" shape. He developed the delivery after being struck in the forearm with a ball in high school by C. J. Woodrow (a former Philadelphia Phillies farmhand). He then began to throw side arm and play shortstop due to his injury. When it healed, he could not change back to over the shoulder and his unique delivery stayed the way it is. He still has a lump in his forearm where he was struck. The delivery has earned mention on SportsCenter as well as Baseball Tonight. Professional baseball scouts have had a divided opinion on the issue. Some were worried that this violent-looking delivery would lead to arm problems. Others considered the delivery to be an asset, as right-handed batters have a very difficult time seeing the ball. For example, Jose Marzan, his former manager with the Single-A Fort Myers Miracle believes that one of Neshek's greatest strengths is his ability to have enough strength to throw hard from such an angle, as his fastball used to top out around 96 mph (154 km/h) prior to his Tommy John surgery. Neshek has had great success in both the minor and major leagues as a reliever, averaging more than a strikeout per inning pitched. After joining the Cardinals in 2014, Neshek's sinking fastball showed effectiveness well-above expectations through May 21. With a mean movement of 10.9 inches, it averaged more horizontal movement than any other pitch from any other reliever on the Cardinals staff, which was 1.3 inches more than Carlos Martinez' two-seam fastball. Martinez' own fastball has been heralded for its movement. Neshek's sinking fastball also averaged over 91 miles per hour (146 km/h) during that time, its highest velocity since 2007.

Did he every try to change it up
When it healed, he could not change back to over the shoulder and his unique delivery stayed the way it is.