The Brisbane Lions ruckman was playing his second game at reserves level on Saturday following a 10-week absence with a knee injury, when he picked up an Achilles problem.
It was the same Achilles he tore early in 2012 that cost him most of the season.
With Leuenberger's poor injury history, the club says it is just being cautious.
Strength and conditioning coach Matt Hass told lions.com.au that Leuenberger was a work in progress.
"It did flare up a little bit on him just before half-time so we took the cautious approach to finish his game there," Hass said.
"We'll monitor him throughout the week and see if he's available."
The Lions have listed the 26-year-old as one week away on their official injury list, so he is unlikely to play at the weekend.
Click here to see the full AFL injury list
Veteran midfielder Brent Moloney also picked up an Achilles niggle from Saturday's NEAFL game against the GWS reserves team and will miss a week.
Moloney has not played seniors since round five after falling out of favour with coach Justin Leppitsch.
