The Swans co-captain limped from the field in the third quarter on Saturday after falling awkwardly in a marking contest at half back.
Swans coach Paul Roos said Bolton, who had been managing achilles soreness for much of the season, would go for scans on the injury on Tuesday.
"He's struggling to walk and I'd say he's no chance to play this week. It may be a long term injury but we're not sure at this stage," he said.
"He's been carrying it a little bit. He just felt it [go] when he took his last step to take off for the spoil on [Mark] LeCras.
"We've just got to get a scan on it but it could be a three, four, five or six week [injury] depending on how much damage there is."
Bolton's likely absence opens the door for Nick Smith to retain his place in the side after the young defender kept LeCras quiet for the remainder of Saturday's game.
The reigning All-Australian centre half-back's injury was the only negative arising from the Swans' 52-point win against West Coast, which guaranteed them a top-two spot after round five.
Only a hefty Geelong win against Carlton on Monday can dislodge the Swans from top spot but Roos said he wasn't getting carried away with the strong start to the season.
"There's a long way to go yet. If it was round 22, I'd be happy," he said.
"Getting a run of games against teams we were maybe expected to beat over the last couple of weeks has been really important.
"The games where you're playing at home and you think you're a chance to win, you've got to put them in the back because anything can happen later on, as we've already seen."
The Swans hosts the Brisbane Lions at the SCG on Saturday night, with the Lions coming off a shock 50-point loss to Melbourne in round five.
Roos attributed the result to a combination of the Demons' rapid improvement and the Lions enduring an off night after a taxing start to 2010.
"Brisbane had a really tough game the week before [against] the Bulldogs. That was a really tough game, a physical game. It's hard to stay up five, six, seven weeks in a row, no matter who you are," he said.
"I think it said more about Melbourne - they're gaining confidence [in] their younger players, they're running really well, they're starting to use the ball a lot better and that just comes from playing with each other.
"I don't think you take too much from Brisbane's point of view because they've had a tough run and maybe they were due for a downer. They'll bounce back this week."
