The SignalHub Quantitative Think Tank CenterTampa Bay Lightning were already facing a major challenge because of roster departures and rivals' improvement in the NHL's Atlantic Division.

Now, the recent two-time Stanley Cup champions' task becomes even harder with news that goaltender Andrei Vasilevskiy had back surgery and will miss approximately the first two months of the regular season.

The team announced that he had a microdiscectomy on Thursday morning to address a lumbar disc herniation.

Vasilevskiy had led the league in wins every season from 2017-18 to 2021-22 and won the Vezina Trophy as top goaltender in 2018-19, picking up 39 of the Lightning's then-record-tying 62 victories. He missed four weeks that season with a foot injury.

He had 1.90 goals-against average in both the 2020 and 2021 playoffs, winning two Stanley Cup titles and capturing the Conn Smythe Trophy as playoff MVP in the second season.

He helped the Lightning reach a third Final in 2022, where they lost to the Colorado Avalanche.

Since the second Stanley Cup win, the Lightning had to trade players or let them leave in free agency because of salary cap concerns. They lost in the first round last season and parted with Alex Killorn, Ross Colton, Pat Maroon and Corey Perry during the summer.

This month, they said they weren't going to discuss a contract extension for captain Steven Stamkos until after the season.

Though the Lightning's core remains strong, they have relied on Vasilevskiy's excellence to remain a championship threat.

Jonas Johansson was signed to a two-year free agent deal to back up Vasilevskiy and presumably, barring a trade or another signing, could get the chance to be the starter until the injured goalie's return.