Grant Dayton To Undergo Tommy John Surgery

Dodgers lefty Grant Dayton is set to undergo Tommy John surgery, Mike DiGiovanna of the Los Angeles Times reports (Twitter link). That will obviously bring his season to a close and will likely keep him out for most or all of the 2018 campaign as well.

Dayton emerged late last year as a force in the Dodgers pen. After years of toiling in relative anonymity, he posted preposterous numbers in the upper minors and then continued to shove at the game’s highest level. Over his first 26 1/3 MLB innings, Dayton worked to a 2.05 ERA with 13.3 K/9 (on a  15.0% swinging-strike rate) and 2.1 BB/9.

That remarkable showing — driven by Dayton’s powerful spin rate and excellent command — seemingly made the southpaw one of the game’s most intriguing relief assets. While he turned 29 not long after his sparkling rookie campaign, Dayton was controllable through at least 2022 and had shown signs of sustainable dominance.

Things simply haven’t gone that way in 2017, however, as Dayton has gone backward in basically every regard. Though he was never a pure velocity guy, Dayton has lost nearly 1.5 mph on his average heater. His vaunted four-seamer spin rate has fallen off. The results followed: Dayton’s swinging-strike rate dropped below ten percent and he posted a 4.94 ERA with a very pedestrian 7.6 K/9 and 4.6 BB/9 over 23 2/3 MLB innings.

Neck issues and an intercostal strain had limited Dayton and could help explain some of his struggles. The elbow trouble, though, apparently cropped up only recently, as Dayton was warming up for a rehab appearance. Because he was on the 10-day DL when the injury occurred, he will continue to accrue MLB service time for the duration of the recovery period for the upcoming procedure.