The Blues traded defenseman Kevin Shattenkirk to the Washington Capitals on Monday night, receiving two top draft picks and a young forward in return.

The possibility of a trade involving Shattenkirk had been rumored ever since last summer because of his status as a potential unrestricted free agent at the end of this season, and the likelihood the Blues would not be able to re-sign him.

Shattenkirk, 28, has been with the Blues since Feb. 19, 2011, when he was acquired in a trade from Colorado.

The Blues will receive the Capitals’ pick in the first round in this year’s draft, a conditional second round pick in 2018 and Zach Sanford, a 22-year-old forward.

Sanford has played in 26 games as a rookie this season for the Capitals. He was a second-round pick in the 2013 draft out of Boston College.

Shattenkirk has been one of the top offensive defensemen in the NHL for years and also is an integral player on the Blues’ power play. He has 11 goals and 31 assists in 61 games this season.

He is just three points shy of matching the best offensive season of his career, when he registered 45 points during the 2013-14 season.

The return for Shattenkirk is not as great as it would have been had the team acquiring Shattenkirk been able to reach agreement on a long-term contract extension.

It was reported last week Shattenkirk had turned down a seven-year deal from the Tampa Bay Lightning.

Going into their home game Tuesday night against the Edmonton Oilers, the Blues trail the Nashville Predators by four points in the race to finish third in the Central Division and a guaranteed playoff spot. With 67 points, the Blues currently would be the second wild-card team in the Western Conference.

The NHL trading deadline is Wednesday.