"I think the unrestricted guys will most likely hit the open market," Armstrong said.

David Backes is one of five impending unrestricted free agents not expected to be signed by the St. Louis Blues before July 1, general manager Doug Armstrong told the St. Louis Post-Dispatch on Saturday.

Backes, the Blues captain, along with forwards Troy Brouwer, Steve Ott, Kyle Brodziak and Scottie Upshall, can become an unrestricted free agent. Brouwer, Upshall and Brodziak each spent his first season in St. Louis in 2015-16.

Armstrong said he is working to retain Backes but at a fair price. The 32-year-old center has been Blues captain since Sept. 9, 2011 and has played all 10 of his NHL seasons with them. He had 21 goals and 45 points in 79 games this season, and has 206 goals and 460 points in 727 regular-season games.

"We'd like to have David back, and hopefully as we push in we can get it done," Armstrong said. "But it has to work for both sides, not just one. We're willing to invest a little bit of 'thank you' money, but it has to make sense. He's earned the right … but only to a level."

Video: STL@DAL, Gm7: Backes pads the lead with great shot

Backes set an NHL-career high with seven goals and 14 points in 20 games during the 2016 Stanley Cup Playoffs. He helped the Blues reach the Western Conference Final for the first time since 2001. They lost in six games to the San Jose Sharks.

Brouwer, 30, had 18 goals in 82 games this season; he was the only Blues player to skate in every regular-season game. He had eight goals in 20 playoff games, including the winning goal in a 3-2 victory against the Chicago Blackhawks in Game 7 of the Western Conference First Round.

Brodziak, 32, scored seven goals in 76 regular-season games and had two goals in the playoffs. Upshall, 32, had six goals and 14 points in 70 regular-season games, and three points in 17 playoff games.

Ott, 33, has played for the Blues since 2013, when St. Louis acquired him and goalie Ryan Miller from the Buffalo Sabres for goalie Jaroslav Halak, forwards Chris Stewart and William Carrier, and two draft picks. Ott has 17 points in 122 games with the Blues.