Gallant was recalled Monday from the Bridgeport Sound Tigers of the American Hockey League, where he had one goal, one assist and 245 penalty minutes in 56 games this season.
Gallant, 25, has played the past four seasons in Bridgeport after being signed as an undrafted free agent. He joins forwards Ryan Strome, John Persson, Johan Sundstrom and Mike Halmo, and defensemen Kevin Czuczman and Scott Mayfield, as Islanders to make their NHL debut during the 2013-14 season. Forward Brock Nelson made his regular-season debut this season after playing one game in the Stanley Cup Playoffs last season.
Islanders coach Jack Capuano confirmed goalie Anders Nilsson would make his second consecutive start. Nilsson made 29 saves in a 4-0 loss Sunday to the Columbus Blue Jackets which snapped a personal three-game winning streak.
The Senators, who remain mathematically alive in the Stanley Cup Playoff race, will counter with goalie Craig Anderson. One more point lost by the Senators or gained by the Columbus Blue Jackets, who host the Phoenix Coyotes on Tuesday, will eliminate Ottawa.
Senators forward Colin Greening, who has missed the past five games with a lower-body injury, took part in an optional morning skate but will not play. Defenseman Jared Cowen, also battling a lower-body injury, may miss the rest of the season.
"Colin won't play tonight, we're going to still be guarded and careful with him," coach Paul MacLean said. "Everything else, we're going to make a decision, possibly one more change at forward (Matt Kassian), but we haven't made a decision on that yet. Everything else will remain the same."
Here are the projected lineups:
Scratched: Matt Kassian
Scratched: Radek Martinek