Karlsson, last season's Norris Trophy winner, was retrieving the puck in a corner Wednesday night when the skate of Pittsburgh's Matt Cooke sliced into the back of his left foot. Karlsson required surgery Thursday to repair his Achilles tendon, which was 70 per cent cut by Cooke's blade.
"I had trouble watching it to be honest with you," Calgary Flames forward Michael Cammalleri said of Karlsson's injury. "I got cut above the knee in the first game of last season and ever since, I've been completely paranoid.
"I wear cut-proof socks and wrists guards and everything now because of it."
Either cut-proof or cut-resistant socks are available, but many players find them uncomfortable and don't wear them.
Short-track speed skating is another sport where skate cuts are common.
Competitors wear full, cut-proof suits. But Canadian national team member Francois Hamelin was sidelined this season after requiring several stitches to close a foot cut caused by one of his own skates in a crash at a World Cup meet in Japan in December.
"Hockey skates and speed skating blades are really sharp," said Hamelin. "We have longer blades so it can go deeper, but (Karlsson's) cut was pretty bad.
"My cut was less bad. It was just in a bad place, on my foot."
Hamelin was wearing cut-proof socks but the blade went through a part of the boot that wasn't protected.
Many NHL teams have lost players to skate cuts for extended periods.
Markov missed four months after having a tendon in his left ankle sliced by Habs goalie Carey Price's skate in a collision early in the 2009-10 season. Another Montreal skater, Robert Lang, had his season end Feb. 2, 2009 when he severed his left Achilles tendon.
Bieksa has twice been out because of skate cuts. He had his right calf slashed by Nashville Predator Vern Fiddler's skate in a game Nov. 7, 2007, then had his left leg cut while checking Peter Prucha of the Phoenix Coyotes on Dec. 29, 2009.
With files from Donna Spencer in Calgary.