Kay underwent Tommy John surgery Tuesday and will miss the entire 2017 season, Anthony DiComo of MLB.com reports.
It seems that the initial speculations regarding Kay's elbow were spot-on, as the supplemental-round draft pick did in fact have some damage to the ulnar collateral ligament in his elbow. It's a shame that the Mets will lose the left-hander for an entire season a mere four months after drafting him, but if all goes well in his rehab process, Kay should have plenty of time to prepare for the 2018 season.