The 35-year-old limited-overs specialist is in pain and admits he came back too early after suffering the injury on February 3.
“It is still broken. I had an x-ray yesterday,” Lee told reporters on Thursday. “The show must go on. You’ve got to do these things when you’re playing for your country.
“It has been very painful. I’ve come back a lot earlier than I probably should have, but you have to do that when you’re playing for your country.”
Lee hurt his foot while fielding during a Twenty20 International against India in Melbourne.
The injury was expected to require at least a month on the sidelines but the NSW speedster returned to action in an ODI against Sri Lanka in Sydney two weeks later.
Lee has claimed five wickets in four games in the series but could find himself having a rest on Friday as Australia host Sri Lanka at the MCG in the last game before the finals.
Fit-again paceman James Pattinson is expected to push strongly for a spot in the team on Friday on his home ground with Lee, Clint McKay and Ben Hilfenhaus all contenders to miss out.
“Hopefully, I’ve been doing my job and playing some decent cricket,” Lee said. “We have got a great squad of players and some serious depth so we’ll wait and see what happens tomorrow night.”
Australia (19 points from seven matches) lead India (15 from eight) and Sri Lanka (15 from seven) with one game remaining before the best-of-three finals series.
Michael Clarke’s men will host either Sri Lanka or India in game one of the finals in Brisbane on Sunday. A home-town win on Friday over Sri Lanka will put India into the finals.
Clarke nursed a back injury and was restricted to walking laps of the MCG at training on Thursday, which suggests Shane Watson will be acting captain for a second consecutive match.
Meanwhile, Lee says the recent sacking of 37-year-old former captain Ricky Ponting from the one-day side hasn’t deterred him.
“Everyone is the chance of being under a lot of pressure at some stage of their career,” Lee said.
“I laugh every time I’ve been written off. I’ve been written off for the last 15 or 16 years but I’m still standing.”
Some would argue if Lee isn’t part of Australia’s 2015 World Cup plans, it’s time for the 2003 World Cup winner to go.
“I’m not looking too far ahead. Age shouldn’t be a barrier,” the 209-game veteran said. “If someone’s good enough at the age of 35 to 36, 40 years of age, who cares? It comes down to form.”