McGrath is recovering from two ankle operations and has not played since the second test against Bangladesh in Cairns in July, while Lee is on the way back from ankle surgery and torn stomach muscles sustained during the second Test against Zimbabwe in Sydney in October.
A Cricket Australia spokesman said on Wednesday that McGrath was "further advanced" than Lee but it was too early to say whether the pair would be fit for the December 4-8 Test in Brisbane.
Both could still be named in an extended squad on November 27 before facing fitness tests.
Fast bowler Jason Gillespie, however, returned from a side strain for South Australia on Tuesday.
Gillespie bowled his first seven overs for 10 runs and finished with two for 46 off 19 overs in New South Wales' first innings of 267 in Adelaide.
If Lee or McGrath are ruled out, Queensland's Andy Bichel is expected to start with Brad Williams and Nathan Bracken, who have impressed on Australia's one-day tour of India, next in line.
