The Brisbane Lions ruckman has been ruled out of Friday night's NAB Cup final against Carlton, pulling up sorer than expected following a match against GWS on March 2.
It was Leuenberger's first competitive hit-out since sustaining the injury in round three last season against Fremantle.
The Lions kept the 24-year-old in cotton wool towards the back end of last year to ensure he completed the majority of the pre-season, which he has done.
He is currently waiting on scans to confirm whether there is any further damage to the Achilles.
"He's had a pretty good run over the pre-season, just had a minor hiccup and we think we'll get him going again Thursday," assistant coach Adrian Fletcher said.
"It's not serious at all. We've just got to make sure when it's in that area of the body, you've got to make sure you don't have a hiccup."
Fletcher admitted that even two full weeks of training between now and the Lions' round one date with the Western Bulldogs on March 30, might not be enough.
"We're going to give him the best chance to be ready," Fletcher said.
"We go back to three interchange players on the bench and that will make it a little more difficult. He's an important component to our set-up, especially in the ruck, and that means we can play Stefan Martin forward, and that gives us good structure."
New midfield recruit Brent Moloney said having the 204cm ruckman unavailable was a blow.
"Obviously we'd like to have him out there … but hopefully he'll be right for round one and that's the main focus for us right now."
The Lions completed their main training session in Brisbane on Tuesday before heading to Melbourne on Thursday.
Fletcher said although the Lions were out to win the silverware, they still had their eyes fixed on round one.
"We've had good form in the pre-season, but we know that round one is a different intensity," he said.
"This will be closer to a round one hit-out for us and it's a good test for our boys against a good outfit under Mick Malthouse, who is a smart character."
Matthew Leuenberger is a ruckman in NAB AFL Fantasy. He averaged 56.7 points in 2012. Register your team at our AFL Fantasy Hub.
