Florida trails the best-of-7 series 1-0.
Sergei Bobrovsky, who allowed five goals on 40 shots in a 5-4 loss in Game 1 on Sunday, will back up Driedger.
"'Driedge' has been in that position, even last year at the end of the year he was under consideration and all year long he did everything you would want," Panthers coach Joel Quenneville said. "He hasn't had this chance here for two years so we feel it's the right time to give him an opportunity based on his performance and based on the opportunity."
Driedger was 14-6-3 with a 2.07 goals-against average, a .927 save percentage and three shutouts in 23 games during the regular season. He last played in Florida's regular-season finale against Tampa Bay on May 10, making 30 saves in a 4-0 shutout.
Driedger, who turned 27 on Tuesday, was 2-0-1 with a 2.33 GAA and a .913 save percentage (seven goals allowed on 80 shots) in three games against the Lightning this season.
"All year long it was the same thing, 'Bob' was fine and Driedge was more than fine in that regard if comparing the two of them," Quenneville said. "It's been back and forth all year, and we said going into the playoffs this year it was based on how he played and the team in front of him as well. It's a very competitive series, a lot of action. He's played extremely well in the Tampa games (in the regular season). It's moreso not what Bob has done but what Driedge has done to earn this opportunity. That's where we're at."
Selected by the Ottawa Senators in the third round (No. 76) of the 2012 NHL Draft, Driedger is 21-9-4 with a 2.09 GAA, a .929 save percentage and four shutouts in 38 regular-season games (34 starts).
It will be Driedger's first playoff game as a professional. The last time he played in the postseason was Game 6 of the 2014 Western Hockey League playoffs with Calgary against Kootenay on March 29, 2014.
