Greater Western Sydney veteran Ryan Griffen may be sidelined for the remainder of the AFL season after undergoing surgery on his ankle.

The star midfielder was nearing a return from the syndesmosis injury suffered in April, but he relapsed during weekend training.

Griffen will sit out the next three months, meaning he could make a return for finals in September.

“It’s a more severe injury this time around and required surgery, which he underwent on Monday,” Giants performance boss David Joyce told the club’s website.

Unfortunately during a drill at training, he’s re-injured the ligaments at the top of his ankle.”

Griffen has not played since round three.

The ladder-leading Giants are also without stars Brett Deledio, Devon Smith and Stephen Coniglio due to injuries.

But forwards Steve Jonson (knee) and Rory Lobb (groin) are a chance return against Carlton at Etihad Stadium on Sunday, pending fitness tests.