by John Viril—
Kansas City Royals ace James Shields has been struggling for awhile now.
He dominated opponents until this May 27 start against St. Louis. However, he’s had a much harder time ever since. Though he’s had good results until Tuesday’s 6 run debacle against the Twins, his peripheral numbers indicate declining effectiveness.
Up to that St. Louis start, James Shields had a 2.47 ERA, .247 BA against, and a .580 OPS against. In the 14 starts since, Shields is 4.11 ERA, .292 BA against and .793 OPS against.
That’s a big decline.
Both Jeff Zimmerman of Royals Review and Ben Nielson have written about this issue, but both failed to identify the cause. Nielson wrote about the problem, but admited he could not find a satisfactory answer. Zimmerman tabbed a varying release point as the culprit, while noting that there had been no decline in velocity.
Neither, however, mentioned that Shields has lost about 4 mph of velocity on his cut fastball—which we can see on this velocit...