Pirates director of sports medicine Todd Tomczyk said that Johnson will undergo left knee surgery Thursday, Colin Beazley of the Pittsburgh Post-Gazette reports.
According to Danny Demilio of PittsburghBaseballNow.com, Johnson will require an ACL reconstruction plus an LCL procedure on the knee, which he injured during an Aug. 8 game with Triple-A Indianapolis. Tomczyk said that a timeline for Johnson's return will be established once surgery is completed, but given that the operation will address damage to multiple ligaments, the 22-year-old will likely remain out well into the 2027 season. Johnson hit .198/.332/.319 with eight home runs and 24 stolen bases over 95 games with Indianapolis before the knee injury ended his season.