Per Marc Topkin of the Tampa Bay Times, Honeywell has been diagnosed with a torn ulnar collateral ligament, and Tommy John surgery is recommended.
Honeywell noted he will seek a second opinion but intends to have the procedure done "as soon as possible," per Topkin.
Rays manager Kevin Cash said Thursday that Honeywell suffered a strained right forearm after throwing approximately 10 pitches during a live batting practice session, per MLB.com's Bill Chastain.
"He was throwing pretty good; he was throwing perfect," Rays catcher Jesus Sucre said. "He threw a changeup first pitch to Wilson [Ramos]. Next pitch [was a fastball and] he was screaming."
Honeywell is ranked as the No. 12 prospect entering 2018, per MLB.com. The right-hander was on the cusp of reaching the big leagues after posting a 3.64 ERA with 152 strikeouts in 123.2 innings over 24 starts at Triple-A Durham last season.