On Monday, Maple Leafs coach Mike Babcock said Andersen, who injured his knee in a 4-2 win at the Washington Capitals on Saturday, would start against the Penguins, but backtracked following practice Tuesday.
"We'll see for Thursday," Babcock said.
Andersen practiced and took part in drills Tuesday but left after about 20 minutes, which he said was always the plan. He reported feeling good after the workout but did not commit to a timeline for his return.
"We're going to see, don't want to get too far ahead of myself but definitely progressing," Andersen said. "We'll see how it feels [on Wednesday] and then on Thursday, we'll see."
Andersen said he experienced swelling Sunday following the win at Washington.
"During that next day, it swelled up a little bit more so that's really what it is," he said. "Hopefully it's nothing too serious, but it is preventing me from being in some of the positions I need to be in as a goalie."
He took part in the morning skate Monday but was scratched for a 4-1 win against the Los Angeles Kings. Garret Sparks started and made 33 saves. Eamon McAdam was recalled from Newfoundland of the ECHL and dressed as the backup. He was loaned to Toronto of the American Hockey League on Wednesday.
Andersen is 4-1-0 with a 3.02 goals-against average and .899 save percentage in five starts for the Maple Leafs (6-1-0), who have the best record in the NHL.
Toronto's next game after Thursday is at home against the St. Louis Blues on Saturday.
