TAMPA — There were expected to be fireworks Thursday night when two of the league's most dynamic and skilled teams went toe-to-toe.Just not this kind.The Lightning lost to the Stars 5-3 before 19,092 at Amalie Arena, its second straight defeat. But more important, Tampa Bay also lost top defenseman Victor Hedman, whose head got hit hard into the boards on a shoulder-to-chest hit by Stars captain Jamie Benn with five minutes left in the second period. Hedman skated off slowly under his own power but did not return. Cooper indicated Hedman went through the concussion protocol and told the coach afterward he was "okay." But Cooper said more won't be known until today and it was too early to speculate. That didn't stop his teammates from fearing the worst. PROFILE: Meet the 2015–16 Tampa Bay Lightning — Victor Hedman "It's a big loss to our team, but that's an obvious statement," center Brian Boyle said. "We're concerned for his well-being. We want him to recover so he can get healthy, especially with what the injury might be."Said Steven Stamkos: "You can't replace a guy like that."Tampa Bay (3-2-0) might have to replace two defensemen. Nikita Nesterov is potentially facing a suspension for his check from behind on Stars forward Curtis McKenzie moments after the Hedman hit. Nesterov got a five-minute penalty and a game misconduct. He was unavailable for comment. McKenzie was helped off the ice with a lower-body injury and taken to a hospital, where he was in "excruciating pain," coach Lindy Ruff said. Stars forward Jason Spezza called Nesterov's hit "pretty dirty. … It becomes more bad blood when something like that happens."The Lightning could make a defense callup or two before Saturday's game against Buffalo, possibly Slater Koekkoek or Luke Witkowski. Despite playing with just four defensemen for the final 25 minutes — Boyle filled in admirably — the Lightning rallied back from a 4-1 deficit to cut it to one nine minutes into the third. That's when Stamkos scored his second goal of the game (fourth of the season), both set up beautifully by linemate Jonathan Drouin, who has a team-high six points.But less than two minutes later, Spezza sealed the deal, his backhand trickling through goalie Ben Bishop, appearing to get deflected off Lightning defenseman Matt Carle's stick."I thought the guys did a good job of battling, and they needed a big save by me, and I didn't do it," Bishop said. "One of those nights."Considering the Stars racked up 52 shots in their Tuesday win over Edmonton, the Lightning did pretty well in holding them to 22. And Tampa Bay had its share of chances (70 shot attempts), including hitting two posts, with goalie Kari Lehtonen having a stellar game (30 saves).But the Lightning's special teams cost it. The power play went 0-for-2, struggling to sustain possession. And the leaky penalty kill gave up two more goals, making it seven total allowed in 15 opportunities this season. "It costs us games," Boyle said. "That's a major concern."So is the health of Hedman, a Norris Trophy-caliber defenseman the Lightning an ill afford to lose. Stars 2 2 1 5 Lightning 1 0 2 3 First Period — 1, Tampa Bay, Stamkos 3 (Drouin), 2:24. 2, Dallas, Seguin 1 (Jokipakka, Ja.Benn), 8:58. 3, Dallas, Ja.Benn 3 (Spezza, Seguin), 14:14 (pp). Penalties — Klingberg, Dal (holding), 10:34; Namestnikov, TB (holding), 13:20; Roussel, Dal (cross-checking), 17:15. Second Period — 4, Dallas, Eakin 3 (Janmark, Sceviour), 9:34. 5, Dallas, Demers 1 (Eakin, Hemsky), 18:12 (pp). Penalties — Moen, Dal (roughing), 15:56; Boyle, TB (roughing), 15:56; Nesterov, TB, served by Drouin, major-game misconduct (check from behind), 15:56. Third Period — 6, Tampa Bay, Namestnikov 1 (Stamkos), 7:06. 7, Tampa Bay, Stamkos 4 (Drouin, Boyle), 8:44. 8, Dallas, Spezza 4 (Hemsky, Goligoski), 10:29. Penalties — None. Shots on Goal — Dallas 9-8-5—22. Tampa Bay 6-15-12—33. Power-play opportunities — Dallas 2 of 3; Tampa Bay 0 of 2. Goalies — Dallas, Lehtonen 2-0-0 (33 shots-30 saves). Tampa Bay, Bishop 3-2-0 (22-17).