Vasilevskiy, a 2018 Vezina Trophy finalist, has missed Tampa Bay's past 11 games. The original recovery time for his injury is 4-6 weeks.
"When he gets skating here soon we'll know a little bit more, but in the end even when he does get on the ice there's still a long process after that," Cooper said. "So we're just inching our way closer."
Backup goalie Louis Domingue has filled in capably in Vasilevskiy's absence. He is 12-4-0 with a .903 save percentage and has won nine of 11 starts since Vasilevskiy's injury. Domingue is expected to play when the Lightning host the Colorado Avalanche at Amalie Arena on Saturday (7:30 p.m. ET; SUN, ALT, NHL.TV). In the one game Domingue didn't start,
Edward Pasquale
, a 28-year-old making his NHL debut, got the win when the Lightning defeated the Detroit Red Wings 6-5 in a shootout on Tuesday.
Defenseman Anton Stralman also remains out with an upper-body injury. He has missed the past 13 games and is waiting for another re-evaluation.
Vasilevskiy and Stralman each participated during Tampa Bay's optional morning skate Saturday; Cooper said nothing had changed regarding when they could return.
The Lightning are planning to have Vasilevskiy join them for their four-game road trip that begins at the Winnipeg Jets on Dec. 16 and taking part in practice.
Defenseman Ryan McDonagh said the injuries have made the Lightning put additional emphasis on defense.
"It's not like you necessarily change your game plan or anything or play any different in front of any goaltender," he said. "But we're definitely focusing on the defensive end and not giving up odd-man looks."
