Stephen Holder of The Athletic provided details of Hilton's injury as the Colts attempt to get their roster to 80 players.
The 30-year-old suffered numerous injuries in 2019, missing a Week 4 game with a quad injury and another five with a calf ailment. Of note, Hilton told reporters (h/t Zak Keefer of The Athletic) that he played through a two-centimeter calf tear.
Hilton missed three midseason games with the calf injury but returned in Week 12 against the Houston Texans. He then aggravated that injury and missed two more games before coming back in Week 15.
Hilton is a major loss, as the ex-Florida International star has game-breaking potential, especially on the Lucas Oil Field turf where he has made a living dominating opponents with long receptions.
Given the injury is considered mild, it's unlikely Hilton will miss any games once the regular season begins.