CARLTON defender Zac Williams is facing a race against the clock to return before September, despite avoiding a disastrous secondary Achilles injury during Sunday’s win over Greater Western Sydney.

Scans on Monday confirmed a high-grade calf strain, not a repeat of the Achilles rupture that kept Williams out for almost the entire 2018 season, but he is still expected to be sidelined for up to three months.

"We took the time to get Zac back to Melbourne and get a scan today to assess the injury fully, which unfortunately has confirmed he will be out of the side for an extended period," Blues footy boss Brad Lloyd said.

GIANTS v BLUES Full match coverage and stats

"Zac is understandably disappointed given the work he’s done to get himself playing good football and performing an important role as part of our back six.

"We’ve had a number of personnel changes over the opening nine rounds but to the players’ credit they have adapted and there will be another opportunity for someone to step up and take their chance at senior level."

Carlton, which currently sits inside the top-four and is heading towards its first finals campaign in nearly a decade, has a number of important senior players facing a race against time to potentially play in the post-season.

Mitch McGovern is battling a three-month hamstring injury, Marc Pittonet is recovering from a PCL problem, Luke Parks has a long-term foot issue, while Oscar McDonald is out indefinitely with a back injury.

Harry McKay (knee), Ed Curnow (calf), Jack Martin (calf), Liam Stocker (shoulder), David Cuningham (knee) and Caleb Marchbank (knee) have also dealt with injury setbacks throughout the early stages of the year.