Patrice Bergeron and Daniel Paille scored 20 seconds apart a few minutes after Stamkos was taken off the ice on a stretcher with a broken right leg, and the Bruins beat the Lightning 3-0 on Monday afternoon.
Stamkos was hurt with 7:11 to play in the second period. He entered the day tied with Pittsburgh's Sidney Crosby as the NHL's leading scorer. Stamkos got tied up with Boston defenseman Dougie Hamilton and crashed into the right post.
His left skate appeared to hit the post first before his right leg crashed into it around the shin area. He tried to get up twice before going down to the ice in pain, grabbing his leg just above the ankle.
When he left the ice on a stretcher, players on both teams tapped their sticks on ice as the fans applauded in tribute.
''A player like that, I don't know how serious it is, but it looks pretty serious to me,'' Boston coach Claude Julien said. ''You don't want to see that.''
The Lightning confirmed on the team's Twitter account that Stamkos suffered a broken right tibia.
General manager Steve Yzerman said that Stamkos is expected to have surgery on Tuesday.
''At this point Steven will be out indefinitely,'' Yzerman said in a statement. ''The medical staff in Boston, in consultation with our team physicians, has made the decision to surgically repair the injury.
''The procedure is expected to take place tomorrow morning. The biggest concern for me, and the rest of the Lightning, is that decisions are made in Steven's best long-term interest, and we feel this is the appropriate course of action.''
Anders Lindback, playing just his fifth game of the season, made 23 saves for Tampa Bay, which had a four-game winning streak snapped.
''Injuries happen. He's gone a long time in his career without being seriously hurt,'' Tampa Bay coach Jon Cooper said. ''There's no sugarcoating it. He's a huge part of our team. You can make an argument here that if you were going to hand out the MVP in our league now, you can give it to him. Is that a hole in our team? Yes, it is.''
They made it 2-0 when Paille broke in down the right wing, shifted to his backhand and slipped a shot past Lindback inside the right post. During the play, Tampa Bay defenseman Sami Salo also appeared to hurt his right leg and had trouble making it to the bench. He was briefly assisted by one of the referees on the ice and didn't return in the third period.
''Well, I mean that is a big blow for them. Nobody wants to see that happen to anybody,'' Iginla said. ''He was obviously in a lot of pain and I didn't hear for sure what happened to him, but I imagine it's got to be, for him not to get up, he's a tough player and plays hard and stuff. So he must have been in some serious pain.''
Tampa Bay veteran Martin St. Louis didn't know how bad the injury was, but felt his team still played tough.
''I thought we played hard. We just couldn't get the puck in the net,'' he said. ''We really can't think about (Stamkos' injury) now. We've got a game to play (Tuesday). We're going to be playing a lot of hockey. I don't know how bad it is. It's tough to comment.
''We lost him tonight for a period and a half. I think it's a big part of our team. I thought we battled.''
It was Tampa Bay's second loss in nine games. The Lightning came into the day leading the NHL's Atlantic Division, but the loss of Stamkos will be a major blow.
''Now we've got to pick ourselves up and see what we're made of,'' Cooper said. ''It's a tough one for the game. You want to see guys that have `It' and Steven Stamkos has `It.' Now we'll see what we're made of. You talk about a test, this is a test.''
Boston won its third straight.
NOTES: Stamkos' streak of scoring a goal was stopped at six games. ... Boston won its seventh straight against Tampa Bay. ... The Bruins' Krug, Dennis Seidenberg, David Krejci, Johnny Boychuk and Matt Bartkowski each bought $2,500 of tickets that were given to military members and their families, who had a chance to meet the players after the game. ... It was the 80th meeting between the franchises. Boston has won 51. ... The Bruins wore military-style camouflage jerseys during warm-ups. ... It was the Lightning's second of a three-game road trip. They play at Montreal on Tuesday night. ... Boston is off until hosting Columbus on Thursday. ... The game was the opener of an NHL-NBA doubleheader. The Celtics were slated to face Orlando at night.