The Colorado Avalanche center said he took a puck off the foot and had "a couple" of MRIs on Thursday. He did not specify when the injury happened.
"It's not broken, it's just really sore," MacKinnon said. "Swollen still, so I'm not going to force it this weekend."
The Avalanche captain said he will be able to play in Colorado's next game, against the Vancouver Canucks on Feb. 2, after their mandatory five-day break that begins Monday.
MacKinnon, who is tied with Patrick Kane of the Chicago Blackhawks for fifth in the NHL with 71 points (27 goals, 44 assists), was replaced by Kendall Coyne Schofield of the U.S. Women's National Team in the Bridgestone NHL Fastest Skater at the 2019 SAP NHL All-Star Skills on Friday. Coyne Schofield, a forward, won gold with the United States at the 2018 PyeongChang Olympics and silver at the 2014 Sochi Olympics.
"I get killed every year, so I'm happy I don't have to do it," MacKinnon said of the Fastest Skater. "Connor (McDavid, of the Edmonton Oilers) is so fast. He kills me every year."
McDavid won the Fastest Skater for the third straight season on Friday. MacKinnon finished fourth in 2018 and lost head-to-head in a heat against McDavid by six-tenths of a second in 2017.
MacKinnon, who arrived in San Jose on Friday, is on the Central Division roster with his linemates Mikko Rantanen and Gabriel Landeskog. This was the third consecutive time MacKinnon was named to the All-Star Game.
"I love coming to this," he said. "It's still fun. Still the captain. Going to get my jersey on, get a couple pictures."
