SAN DIEGO — The Phillies signed Kevin Gowdy, a prep pitcher, for an over-slot bonus of $3.5 million last summer. His professional career, to this point, has consisted of a mere nine rookie-ball innings. It will be quite some time before he pitches again.

Gowdy underwent Tommy John surgery Tuesday in California. The righthander will likely miss all of 2018. Neal ElAttrache performed the surgery in suburban Los Angeles.

The Phillies selected Gowdy with the 42nd overall pick in 2016. They chose Mickey Moniak at No. 1, in part, to save money for a larger bonus to sway Gowdy from his college commitment to UCLA. Gowdy turns 20 in November.

Gowdy had not pitched in a game this season because of various injuries. He was limited to four appearances in the Gulf Coast League last summer because of an injury. The typical recovery time for Tommy John surgery is 12-16 months.

Moniak, 19, has hit .248 with a .656 OPS at low-A Lakewood. Third baseman Cole Stobbe, the team's third pick in that draft, is hitting .171 with a .583 OPS at short-season Williamsport.