TAMPA — There's no question the Lightning had interest in Senators superstar defenseman Erik Karlsson at Monday's trade deadline.General manager Steve Yzerman had conversations with Ottawa about landing the two-time Norris Trophy winner. But you get the sense that Tampa Bay was never really close to getting Karlsson, 27, at least not for the franchise-player price the Senators were hoping to get.And that might not be a bad thing.Acquiring defenseman Ryan McDonagh, 28, from the Rangers was far from a fallback option. It might have been the Lightning's best one."I think he's a better fit," said former Lightning goalie Ben Bishop, now with the Stars. "Karlsson is great. But in the playoffs, you want more of a shutdown guy. (McDonagh) can do everything — plays the power play, penalty kill, last minute (of games). Now you've got four (defensemen) you can put out there in any situation."It's hard to tell how McDonagh, who has been out with an upper-body injury, will slot in on the blue line until he makes his Lightning debut, which could come Tuesday against the surging Panthers. He could play with former Rangers defense partner Dan Girardi. He could play the right side with rookie Mikhail Sergachev.No matter what, McDonagh will play a large role."McDonagh is one of the most well-rounded defensemen in the league," said two-time Stanley Cup-winning defenseman Brian Engblom, the Lightning's Fox Sports Sun color analyst. "He's a No. 1 on any team — a 1A-1B with Victor Hedman, and that's only because Victor is Victor. (McDonagh) thinks about the right net first."That doesn't mean he's not good passing the puck or making plays. He can play in any situation. He's really mobile, really smart. He covers up a lot of mistakes by other people. He's pretty much everything you want to list in an all-around defenseman. He can play against somebody as big as (6-foot-3, 224-pound Kings forward Anze) Kopitar, or somebody as fast as (Islanders rookie Mathew) Barzal."McDonagh, a leftie shooter, can play the left and right sides, which could help a blue line with more depth on the left. Think about it this way: No matter how you slice it, the Lightning can ensure that either Hedman, McDonagh or Anton Stralman is on the ice at any time.And having McDonagh could give Hedman a break, too, whether that's on the penalty kill or power play. Hedman played nearly 30 minutes Monday against the Maple Leafs."(McDonagh) takes pressure off Hedman," said former NHL GM Craig Button. "Doesn't put excessive demands on Sergachev, Stralman and Girardi. Slots everybody nicely. Ryan is a very good passer, and with the quality of (the Lightning's) forwards, that is a quality that makes them more effective."And don't forget, Karlsson could be available again at June's draft or as a free agent in 2019.Slap shots• Though the Lightning lost 2016 first-round draft pick Brett Howden and defense prospect Libor Hajek in the McDonagh trade, its prospect pool is far from bare. A Western Conference scout who has seen a lot of AHL Syracuse this season said Anthony Cirelli, who had a dazzling NHL debut Thursday against the Stars with a goal and an assist, was the team's best two-way forward, and one of six Crunch prospects likely to make the NHL (the others: Mitchell Stephens, Alex Volkov, Mathieu Joseph, Erik Cernak and Dominik Masin). That doesn't include junior standouts Taylor Raddysh, Cal Foote and Otto Sompi.• It'll be interesting to see how long the Lightning carries nine defensemen once McDonagh debuts. Sitting up to three defensemen a game is not ideal, but Yzerman doesn't want to lose one for nothing on waivers (and he likely would if Slater Koekkoek or Jake Dotchin were available). Yzerman can still trade one of them, though they wouldn't be eligible to play the rest of this season in the NHL. For now, they're in limbo.• With backup goalie Peter Budaj (upper body) really close to returning, a tough decision is looming for the Lightning. Louis Domingue, called up in late December to replace Budaj, has played well, winning four of his six starts (all on the road). With Budaj in the first year of a two-year deal signed last summer, it makes sense for him to regain the backup role. Domingue can still get sent down to AHL Syracuse without having to go through waivers (until he plays in his 10th game; he's now at seven). But when asked if Budaj would be the backup when he's healthy, Yzerman said only, "We'll have to decide on that at some point."Joe Smith can be reached at [email protected] Follow @TBTimes_JSmith.