TAMPA — Wing Alex Killorn said he spoke with Steven Stamkos after the Lightning captain signed his eight-year, $68 million deal June 29.In likely leaving money on the table in free agency to remain in Tampa Bay, Stamkos sent a message, Killorn said. Defenseman Victor Hedman followed suit July 1 with an eight-year, $68 million extension."It's something special in Tampa," Killorn said. "Everyone wanted to stay together."And that might be even more challenging going forward.But Killorn, 26, joined the core in staying Sunday, the restricted free agent signing a seven-year, $31.15 million deal ($4.45 million annual average) with the Lightning, which drafted him in the third round in 2007. In doing so, Killorn avoided an upcoming arbitration hearing.The former Harvard star gets an annual $2 million bump in salary, up from $2.5 million last season, and security. Killorn has a modified no-trade clause."It's surreal, and it hasn't really sunk in yet." Killorn said. "I could have never imagined signing this contract (years ago)."The Lightning retains a versatile top-six forward who, despite not having a 20-goal season, has been at his best in the playoffs, with 33 points in 47 games."We're very comfortable doing a long-term contract at the right cap number with Alex," general manager Steve Yzerman said. "He's been with us his entire career. He's a high-character young man, tremendously fit and part of the core of our team. We're trying to keep the core together as much as we can."Now comes the tricky part. The Lightning has just $8.5 million salary cap space left for next season, according to the salary cap website capfriendly.com. To keep his remaining free agents, including Nikita Kucherov, and stay under the cap, Yzerman said he'll likely have to make a trade this summer. And the next offseason might be even tougher, with Tyler Johnson, Jonathan Drouin and Ondrej Palat due to be restricted free agents.Yzerman said the team intends to re-sign restricted free agents Kucherov, center Vladislav Namestnikov and defenseman Nikita Nesterov but offered no update. Namestnikov has an arbitration hearing scheduled for July 29."We'll certainly try to get it done before the hearing," Yzerman said. "But if we have to go, we have to go."Kucherov, coming off a 30-goal season, is due a hefty raise from the $700,000 he made last season, potentially to the $6 million range. Yzerman has said he's confident both sides can reach an agreement, but nothing appears imminent.How does Tampa Bay create cap space? Veteran center Valtteri Filppula, with a $5 million hit the next two seasons, is a strong candidate to be moved, especially if Namestnikov is signed. Other players with trade value include defenseman Jason Garrison ($4.6 million the next two years) and goaltender Ben Bishop, who is entering the last year of his deal at $5.95 million. Backup goalie Andrei Vasilevskiy was signed to a three-year extension on July 1. Yzerman has said he likely would have to trade a goalie or risk losing one before the June expansion draft.Asked if there has been clarity on the goalie situation, Yzerman said, "Things are very quiet right now. We're more than happy to go into the season with both goalies."With Stamkos, Hedman, Vasilveskiy and Killorn signed to extensions in the past month, the Lightning will have $20 million in cap space left for 2017-18 if the cap remains the same at $73 million.The Lightning won't be able to keep everyone, but it will probably need others to follow Stamkos' lead."He's the captain of our team, one of the best, if not the best, players in the league," Killorn said. "I don't know how much a (pay) cut he took, but it was pretty substantial. It's just one of those things in a salary cap system, if you want to keep a team intact, want to keep guys, guys have to take a little bit less. It's the way it is. I think (Stamkos) did a good job leading off, showing how much he wanted to stay." Contact Joe Smith at firstname.lastname@example.org. Follow @TBTimes_JSmith.