TUKWILA, Wash. — It’s now certain that Clint Dempsey’s 2016 season is over and his future beyond this year may be in doubt too.

The Seattle Sounders announced Tuesday that Dempsey will miss the remainder of the season due to an irregular heartbeat that has sidelined him for more than a month.

Seattle general manger Garth Lagerwey made the announcement ahead of Wednesday’s home match against Chicago as the Sounders are contending for one of the final playoff spots in the Western Conference.

“We simply haven’t got to a point where we were comfortable that there was a realistic chance” of Dempsey returning this year, Lagerwey said. “As we said in the first round of comments, we are not comfortable putting any kind of pressure on this. His return to play is not important relative to his health, both short- and long-term. We feel by ruling him out today it puts us in the best position to get him back hopefully for the start of the 2017 season.”

Seattle announced on Aug. 26 that Dempsey, 33, would be out due to an irregular heartbeat revealed after a series of tests. Lagerwey said Dempsey had been undergoing tests for a couple of months before the issue was discovered.

Since the diagnosis was announced, Dempsey underwent an unspecified procedure and has been receiving treatment in Seattle and outside the area. He briefly returned to training about two weeks ago but was gone all of last week.

“He was still undergoing an evaluation and that’s why he had not been cleared to return to play,” Lagerwey said. “That evaluation is ongoing and again, we haven’t gotten to a point where we felt comfortable continuing. We just at this point want to remove any pressure for him to play because we have to get him healthy.”

The decision also rules out Dempsey from consideration for a pair of World Cup qualifying matches for the United States in November, including a showdown with Mexico on Nov. 11. Lagerwey said the club has been in regular contact with U.S. Soccer regarding Dempsey’s condition and treatment.

Lagerwey reiterated there would be no further update about Dempsey’s health coming from the team until the 2017 preseason. Dempsey is under contract with the club through next season.

“The players are friends with Clint so they probably know more than I know. So I don’t think the message was that big of a shock to anybody,” interim Seattle coach Brian Schmetzer said. “I think it’s just a sad story because he’s an integral part of the team, an important part of the team.”

Dempsey is in his fourth season with the Sounders and has eight goals and two assists this year. Seattle is in seventh place in the Western Conference, three points behind Portland for the final playoff spot. But Seattle has two games in hand beginning with Wednesday’s game against Chicago.

“We’re playing well right now. We’re getting some great results. Still have some work to do to get into the playoffs but we’ve begun scoring goals from multiple positions and multiple players and that is how you replace Clint Dempsey,” Lagerwey said. “We don’t have another player on the roster, and there aren’t that many players in the league and the world that are at his level, so we need to replace his production collectively.”