The ACT Brumbies are hopeful George Smith will play at least one more game this year despite a knee injury cruelling his hopes of a historic second chance against the British and Irish Lions.

Wallabies champion flanker Smith and inside-centre Pat McCabe were left out of a 25-man Test squad named on Sunday.

Australian coach Robbie Deans included five Brumbies in the initial group in preparation for the three Tests against the Lions.

Uncapped duo Ben Mowen and Christian Lealiifano will get a chance to push claims for their Test debut while Joseph Tomane, Stephen Moore and Ben Alexander also have a chance to take on the Lions. But the selection elation was tempered by Smith and McCabe's knee injuries suffered in the Brumbies' six-point loss to the Waratahs.

Smith faces up to eight weeks on the sideline after damaging his medial ligament, while McCabe could have ruptured his posterior cruciate ligament, and could make a comeback in time to play some part in the series.

Both returned to Canberra in knee braces, and will have scans on Monday. But it appears they will miss the once-in-12-year opportunity to take on the Lions.

For Smith it's a heartbreaking end to his hopes of playing against the Lions for a second time.

For McCabe - who is expected to sign a new two-year deal with the Brumbies and ARU on Monday - it's another injury in a frustrating year that has included a broken neck and torn hamstring.

If 110 Test veteran Smith has damaged his medial ligament, it's likely he won't return to the field until the Brumbies' last regular season game against the Western Force on July 13.

''I'm delighted we've got five guys in the squad, but obviously disappointed for George and Pat,'' Brumbies coach Jake White said. ''All things being equal, we're hoping George will be back for the Force game.''