TAMPA — The Lightning feared the worst with Victor Hedman's lower-body injury, hoping and praying the franchise defenseman wouldn't be out long term.So the team — and its fans — breathed a collective sigh of relief Friday when they found out Hedman is expected to be sidelined three to six weeks after being hurt Thursday against the Flames.This could have been much, much worse."Of all the outcomes, we're somewhat relieved that this is a shorter time frame," general manager Steve Yzerman said.The injury still hurts Tampa Bay (31-10-3). The All-Star defenseman plays nearly half the game and in all situations. "He's our rock back there," coach Jon Cooper said. RELATED: Victor Hedman hurt in loss to Flames. But Hedman's absence is survivable, especially with the significant points cushion the Lightning has built in the standings, entering Friday with a 12-point lead in the Atlantic Division and an eight-point lead at the top of the Eastern Conference. Also, his absence includes the team's five-day bye week that began Friday and its All-Star break Jan. 26-29, which decreases the amount of games Hedman will miss. Though that also means Hedman, selected this week to play in the All-Star Game in Tampa, will miss that chance.With Hedman expected to return by March at the latest, that would give him a month to gear up for the playoffs.However, this three- to six-week stretch without Hedman is an important, and potentially telling, one as Yzerman evaluates his team leading up to the Feb. 26 trade deadline. How the Lightning responds could go a long way in determining how much it needs to bolster its blue line for a Stanley Cup run."That's a fair statement," Yzerman said.The Lightning was likely already looking at addressing its defense before the injury. But now it will get a chance to see how rookie Mikhail Sergachev develops in an even larger role and how Slater Koekkoek responds to regular playing time. And is this an opportunity for Does Jake Dotchin to snap out of his recent struggles? "We're counting on our other seven 'D' to pick up the slack," Yzerman said. "Guys have been waiting for more opportunity. Now they're going to get it." RELATED: No All-Stars are more deserving than the Lightning's Fab Four. The Lightning has been here before. The last time Hedman was out for an extended period, missing a month with a broken finger in 2014, Tampa Bay went 12-4-1 and ended up in the Stanley Cup final. Yzerman said that Hedman's return time depends on how his rehabilitation goes. He won't need surgery.It looked like Hedman's season might have been over Thursday when Hedman's left knee buckled in a knee-to-knee collision with Flames wing Garnet Hathaway. Hedman couldn't put any pressure on the leg and had to be helped into the dressing room.That image sucked the life out of the bench. Time to snap out of it.Sergachev, 19, already has a big role, but it will increase now. He'll slide into to the top defense pairing with Anton Stralman. Sergachev logged 21 minutes Thursday for the second time in his career, and he replaced Hedman on the top power-play unit, handling it well. But Hedman was averaging 26 minutes a game, and others will have to fill that void. That means veteran Braydon Coburn steps into the second pairing, likely with Dotchin. Dan Girardi is expected back from his neck injury after the bye week. MORE LIGHTNING: Struggling Andrei Vasilevskiy can use some rest. The biggest beneficiary of Hedman's absence may be Koekkoek. This is the 2012 first-round draft pick's chance to prove he can be a regular in the NHL. Koekkoek, 23, brings a left-shot and puck-moving ability that Tampa Bay could use. He has seven points in 22 games this season, often the odd-man out as a healthy scratch, alternating with Andrej Sustr."I think Slater needs ice time," Yzerman said. "We've been pretty pleased with how he's played this year. Last year, at the start of the season, we were hoping he or (Nikita Nesterov) would be able to step in that top six. Neither were quite ready to go. (Nesterov was traded early last season.)"But Slater is a better player than he was a year ago. His experience in (AHL) Syracuse and (its) long playoff run (the Crunch made the league final), logging big-time minutes helped him. I'm looking forward to — depending on what (Cooper) does with the lineup — see Slater play more minutes and see how he does." NUTS AND BOLTS: Yzerman said that backup goalie Peter Budaj's lower-body injury, suffered Dec. 29, would keep him out six to eight weeks, meaning a potential mid-February return. Louis Domingue, who replaced Budaj, is expected to go to Syracuse this weekend to get a start or two to keep sharp during the bye week.Joe Smith can be reached at firstname.lastname@example.org. Follow @TBTimes_JSmith.