Tsatas underwent surgery last week and is now facing up to ten weeks on the sidelines, leading to a delayed start to the season for the 18-year-old.
The Bombers drafted the Oakleigh Chargers product with pick no.5 in the 2022 AFL National Draft and has since impressed during his first pre-season at the club.
Elsewhere at Tullamarine, Jake Stringer has had a slight injury setback heading into the season. The 28-year-old has been placed on light duties as pre-season continues, dealing with back soreness.
Stringer featured in the Essendon's match simulation last week, but was absent from main training on Thursday as he deals with the issue.
Despite being placed on light duties, the Bombers are confident the forward will be right to go when their season kicks off on March 19 against Hawthorn.
Stringer played 15 games last season, averaging 13.1 disposals and kicking 25 goals.