The team confirmed the injury Sunday, Brian McTaggart of MLB.com reports.
The procedure has been recommended, and Whitley will get a second opinion, a source told Mark Berman of Fox 26. The recovery time for pitchers is around 12-to-15 months.
Whitley is the club's top prospect and No. 41 in all of baseball, according to MLB Pipeline. However, the 23-year-old's stock has fallen in recent years after being ranked as high as No. 8 in 2018. Whitley posted a 12.21 ERA in 24 1/3 innings in Triple-A during 2019 but didn't pitch last season because of the pandemic.