Source: Stars acquire Jason Spezza

— -- The Ottawa Senators have traded center Jason Spezza and prospect Ludwig Karlsson to the Dallas Stars for forward Alex Chiasson, prospects Nicholas Paul and Alex Guptill and a second-round draft pick in 2015, a source told ESPN.com.

The deal is still pending a trade call, the source said.

Spezza had been on the trading block for weeks after requesting a deal from Ottawa, with both the Stars and St. Louis Blues emerging as two of the most aggressive suitors in acquiring the former Senators captain.

Stars general manager Jim Nill won that sweepstakes, adding one of the top centers available to a lineup that already boasts young pivot Tyler Seguin and star forward Jamie Benn.

The 31-year-old Spezza is coming off a 23-goal, 66-point season for the Senators. He has recorded four seasons of 30 goals or more in his 11 years with Ottawa.

Spezza has one year remaining on a seven-year deal that pays him $7 million annually.

He was one of the top three centers that became available on the trading block leading up to what has already been a wild offseason.

Ryan Kesler was shipped from the Vancouver Canucks to Anaheim Ducks last week, and the San Jose Sharks are dangling Joe Thornton, though he maintains that he would like to remain a member of the Sharks and has a no-move clause that allows him to stay put.

The deal sending Spezza to the Stars comes on the heels of the former first-round pick (second overall in 2001) vetoing a trade to the Nashville Predators last weekend. Senators GM Bryan Murray had a deal in place that would have sent Spezza to the offensively challenged Predators, but he exercised his no-trade clause and nixed the deal, a move that seemed to irritate both Murray and Predators GM David Poile.

After the deal fell through, Poile said he didn't want to pitch Spezza on coming to Nashville if he wasn't interested in playing for the organization.

Now, Spezza has found a home in the Western Conference with a Stars team that surprised many with an encouraging turnaround this season. Dallas lost in the Western Conference quarterfinals in a nasty first-round match against the Ducks.

With Spezza now off the trade market, teams looking to upgrade at center may be thrown into scramble mode. Unrestricted free agent Paul Stastny becomes the most coveted centerman on the market now.

ESPN.com's Pierre LeBrun contributed to this report.