Wallabies coach Robbie Deans says Australia and Reds captain James Horwill will almost certainly sit out the remainder of the rugby season due to a hamstring injury.

The towering lock forward hasn't played since tearing his right hamstring during the Reds Super Rugby victory over the Brumbies last month.

"It does look like he's got a long term injury," Deans told Australian Broadcasting Corp. on Friday.

"It's unlikely he'll play any rugby this year."

Horwill visited a specialist in Melbourne this week and will have further tests Monday to determine the extent of the damage.

Openside flanker David Pocock was elevated to the captaincy in Horwill's absence for Australia's loss to Scotland in Newcastle and subsequent first-test win over Wales last week.

Pocock will lead Australia against Wales in Melbourne in the second test on Saturday, but Deans refused to commit to him as a long-term replacement.

"There's just no point in looking beyond each week," Deans said.

"None of us know what's coming in the future."

He said for the time being, Pocock was adjusting well to the added responsibility.

"Clearly David's done a great job," Deans said.

"He's responded to the challenge and it came around quickly."