The Waratahs have signed lock Mitchell Chapman from Japanese Top League club NTT Docomo as a replacement for injured hooker Damien Fitzpatrick.

The former Reds and Brumbies tight forward joins coach Michael Cheika's squad on a one-year contract, with Fitzpatrick ruled out for the season with a knee injury.

Fitzpatrick’s injury, sustained during the latter stages of rehab from a ACL reconstruction early in 2012 season, is a cruel blow for the promising young hooker, who had been due to return to action next month after a 12-month absence.

Cheika commented: "Unfortunately Damien suffered a setback in his recovery from the original ACL injury that required further intervention.

"Damien will require a specified period of time to ensure that his injury fully recovers.  That will rule him out of most of the coming Super Rugby season but we are planning for him to be back in time to take part in the second half of the Shute Shield season," he added.

With three hookers already at his disposal (Tatafu Polota-Nau and John Ulugia in the main squad and Luke Holmes in the Extended Playing Squad), Cheika opted against a like for like replacement.

He explained: "Mitchell has been brought in to fill a specific profile within our squad.

"I felt we needed a lock who will be able to help share the workload of our two internationals, Kane Douglas and Sita Timani, and offer an experienced partner for our two young locks, Ollie Atkins and Greg Peterson, especially around the set piece.

"I was convinced of this idea when I spoke to Mitch and saw his enthusiasm for another shot at playing Super Rugby. He seems a quality person and I believe he will fit in to our team environment very well," he said.

Chapman made 28 appearances for the Reds and 40 for the Brumbies, and although still uncapped for Australia, he spent five years on the international scene, touring with the Wallabies in 2006 and 2009 and being included among the replacements for the Brisbane Test against Ireland in 2010.

Chapman said: "I've been watching it on TV and the chance to come back and test myself against the best players has been very motivating.

"Specifically with the Waratahs, I know some of the things that Michael Cheika has put in place rugby-wise. Through the grapevine

"I've also heard that it's a positive place to be. Along with how they are looking to play the game, that was something I wanted to be a part of and the main reason for my decision," he added.

Chapman will join the squad following the completion of NTT Docomo's season in early February, in time for the Waratahs' final Super Rugby trial match at home against the Crusaders on Thursday, February 14.