Buchanan will have surgery on Tuesday, with coach Michael Voss suggesting it will be a four- to six-week injury.
Voss rates midfielder Jed Adcock a 50-50 chance of turning out at the Gabba against Carlton on Thursday night after twisting his ankle.
The coach expressed his surprise at the high number of players on both teams who battled cramps in the second half.
“There was a lot, I must admit, more than perhaps normal,” Voss said.
“It just shows the level of intensity goes up even from NAB Cup games to the real season - there’s a real jump.
"And how fast the games have been has been a bit of an eye opener.”
Carlton enjoys a seven-day break before Thursday night’s clash while the Lions have a quick five-day turnaround.
Voss said the shorter recovery period won’t affect the players too much, other than the fact they won’t do any hard training sessions during the week.
“It will be more about our recovery and ensuring that we come in with fresh legs," Voss said.
"Normally by the time we get to Thursday the guys are in pretty good shape so it’s not really much of an issue as long as make sure we get our recovery right.”
Voss earmarked James Polkinghorne, Albert Proud, James Hawksley and Tom Rockliff as the form players in line for a recall.
The coach also sounded a warning for opposition teams, with veteran Luke Power quickly back to his best form.
Power kicked three match-turning goals against the Eagles and collected 20 disposals after spending a month on the sidelines in the latter part of the pre-season with a groin injury.
Voss said the time on the sidelines will be a blessing for the 30 year old.
“You try and encourage Luke to just pull it back from time to time (but) he’s always full throttle and wants to be a part of everything,” Voss said.
“That’s why he has become the player that he has and the fact that he probably missed about four weeks of training just adds to the fact that he can get through the season and he can play nice and fresh.”
