The goalie is in the final season of a two-year contract he signed with the Flames on July 27, 2019, and can become an unrestricted free agent after the season. The 28-year-old is 4-7-1 with a 2.90 goals-against average, .904 save percentage and one shutout in 15 games (12 starts) this season.
Rittich provides depth at goalie for the Maple Leafs, who have been without Frederik Andersen for the past 10 games because of a lower-body injury. In March, Maple Leafs coach Sheldon Keefe said it was the same injury that caused Andersen to miss four games from Feb. 22-March 1.
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During Andersen's absence, Jack Campbell has stepped into the No. 1 role. He is 11-0-0, setting an NHL record for the most wins to start a season, with a 1.88 GAA, .934 save percentage and two shutouts.
Signed by Calgary as a free agent June 13, 2016, Rittich is 63-39-15 with a 2.83 GAA, .908 save percentage and four shutouts in 130 regular-season games (118 starts), and 0-1-0 in one Stanley Cup Playoff game.
"David's a good goalie. Toronto's getting a good goalie," Flames general manager Brad Treliving said Monday. "David was good for us, but again, we look at the David situation ... we have [Jacob Markstrom] here. I had a conversation with David's agent, explored to see if there's a possibility of him coming back, if there's a contract to be done. I think it's fair to say that come year end, he was probably going to look for a fresh start, which is fair. You balance that and say, 'OK, you're going to have a player that more than likely is going to walk at the end of the year, what does the market say?"
The trade was the second the Maple Leafs made Sunday after acquiring Nick Foligno in a three-team trade involving the San Jose Sharks and Columbus Blue Jackets, who received a first-round pick in the 2021 NHL Draft and a fourth-round pick in the 2022 draft from Toronto.
The Maple Leafs (28-10-3) are first in the seven-team Scotia North Division, six points ahead of the Winnipeg Jets, and the Flames (17-21-3) are in fifth, six points behind the fourth-place Montreal Canadiens.The top four teams will make the playoffs.
NHL independent correspondent Aaron Vickers contributed to this report