Jetta dislocated a thumb during a practice match between the reserve grade Essendon and Richmond sides at Craigieburn on Friday.
The 21-year-old, entering his fourth season at AFL level, will be out of action for up to six weeks, meaning he will miss the start of the home and away season.
Essendon’s general manager of football operations, Paul Hamilton, said while Jetta wouldn’t be able to play for several weeks he would be able to maintain his fitness base - a positive as he strived to make an impression in what looms as a make-or-break year.
“It is disappointing for Leroy because he has had his best ever pre-season and unfortunately it is going to keep him out for a number of weeks,” Hamilton told essendonfc.com.au.
“He will be able to keep his fitness up, which you can’t do with a leg injury, so we are lucky from that perspective.
“Obviously there is a period following the operation where you can’t do much because you can’t allow for the extra bleeding and things, but once it has settled down he can join in and run around and build it up from there.
“It is most disappointing from the perspective that he is a player that knows this is an important year for him and he wanted to get off to a good start and unfortunately it hasn’t happened for him.”
Fellow West Australian Travis Colyer is the Bombers’ only other injury concern in what has been a promising summer for Matthew Knights’ team.
Colyer, who joined the club at the end of last season, had hand surgery last month to repair split webbing but he will resume full training next week.
Hamilton said the Bombers were likely to enter 2010 in better shape than recent seasons.
“This year there has been an element of luck but we have also been very well-planned and I have to say that our high performance staff and our medical group in conjunction to our coaching staff have been working so well together and the result of that is you see a lot less soft-tissue injuries,” he said.
“There has been really good planning put in place - the guys are a lot fitter than they were and that helps.
"They have got themselves in better condition and that helps from an injury point of view but there is always an element of luck.”
Leroy Jetta is a $205,100 forward in this year's Toyota AFL Dream Team.
