Selwood had surgery in Brisbane last week to resolve an irritation in his right foot.
He appeared at the Cats' open training session at Simonds Stadium on Monday wearing a moon boot.
"You have niggles all the time, but it probably got to the stage where I just couldn't keep going," Selwood said during a brief pause in his autograph-signing duties.
"It got to the stage where it was niggling too much for January.
"(Being in the moon boot means) it actually looks a lot worse than what it is.
"I am walking around and taking it out of the moon boot when I'm walking around.
"But when I'm on it for long periods of time it's just safest to have it in (the boot)."
Setback for Cats skipper
Selwood isn't planning on being sidelined for long.
"It's hard to say, but I wouldn't have thought it would be any longer than three weeks, so I'll be out there running, hopefully, this time next week," he said.
"It seems a bit Lazarus-like, given the way that I've got the boot on at the moment, but it was a really minor surgery."
The star midfielder is considered a chance to line up in the Cats' final pre-season match against North Melbourne at Simonds Stadium on Friday, March 7.
"I'll play when I'm ready," was Selwood's take on the matter.
Asked whether he'll line up against Adelaide in Geelong's home and away season opener on Thursday, March 20, Selwood said: "Round one? Yeah. Absolutely."
Joel Selwood and moon boot at Geelong's open training day. Picture: Adam McNicol
The captain was reluctant to comment on Steven Motlop's bout of knee tendonitis, but the club's football department confirmed that Motlop flew out to London on Saturday afternoon to see a renowned tendon specialist.
The star half-forward, who narrowly missed out on a berth in last year's All Australian team after enjoying a breakout season, is expected to remain in the United Kingdom for a week.
Motlop is seeing the same specialist who helped cure Josh Cowan's chronic Achilles tendon issues.
While Motlop will be rugged up to brave a typically cold London winter, most of his teammates were put through the ringer in 35-degree temperatures on Monday.
"They're doing a great job," Selwood said as he watched on. "They've been training really well. They've just got to continue that on. It's an important month, January.
"It's good for the group also, having me off the training track and not barking at them all the time.
"There's different leaders that we need to stand up right now, and they're doing a great job of that."
Twitter: @AFL_AdamMcNicol
The star half-forward, who narrowly missed out on a berth in last year's All Australian team after enjoying a breakout season, is expected to remain in the United Kingdom for a week.
Motlop is seeing the same specialist who helped cure Josh Cowan's chronic Achilles tendon issues.
While Motlop will be rugged up to brave a typically cold London winter, most of his teammates were put through the ringer in 35-degree temperatures on Monday.
"They're doing a great job," Selwood said as he watched on. "They've been training really well. They've just got to continue that on. It's an important month, January.
"It's good for the group also, having me off the training track and not barking at them all the time.
"There's different leaders that we need to stand up right now, and they're doing a great job of that."
Twitter: @AFL_AdamMcNicol
