Once one of the best opensides in the world, Smith made 110 appearances for Australia - including all three Tests against the 2001 British Lions tour - before retiring from international rugby at the end of 2010 and going to play abroad.
The 32-year-old stormed back into contention for this year's Lions tour on the back of some brilliant performances for the ACT Brumbies but was stricken with a knee injury on the eve of the initial squad announcement.
A remarkably quick recovery saw him called into the squad after the first Test defeat in Brisbane but he was not considered for last Saturday's second Test in Melbourne, which the Wallabies won to level the series.
"He's had a week of training under his belt, he's had some background with us and yes, he is physically fit enough to be able to be considered," a cagey Deans said.
"We've talked about what George brings previously, it's good to have him in the group. Even last week when he wasn't preparing to play, he offers good value."
Michael Hooper has acquitted himself well after starting both the Tests at openside, while Liam Gill has come off the bench to telling effect, most notably with a key lineout steal at the end of the Melbourne Test.
Having had the better of the battle of the breakdown in Brisbane, though, the Lions took the honours in defeat in Melbourne.
"The Lions responded to our performance in the first one and they really targeted, particularly the wide breakdowns and put us under a lot of pressure," Deans said. "We've got to be better."
Part of the reason for the improvement of the Lions at the breakdown was a superb performance from their captain Sam Warburton, who will miss Saturday's decider in Sydney with a hamstring injury.
Deans said whoever replaced Warburton at openside, most likely Justin Tipuric or Sean O'Brien, would not weaken the tourists.
"They've got quality options and it doesn't matter who they choose, they've got some very good, able replacements," he said.
"In fact I think it was you blokes who were suggesting at the front end that they should have been there in the first instance."
The Lions will name their team for the third Test on Wednesday, the Wallabies on Thursday.
- Sports & Recreation
- British Lions