TUKWILA, Wash. - If the Seattle Sounders are going to make the MLS Cup Playoffs, they’ll have to do it without star forward Clint Dempsey.

Sounders GM and President of Soccer Garth Lagerwey announced on Tuesday that Dempsey will not return this season as he continues to deal with an irregular heartbeat first discovered last month.

Lagerwey: "If we prioritize this now, hopefully we can get Dempsey back in 2017." — Sounders Beat (@SoundersBeat) September 27, 2016

Dempsey, 33, has been sidelined with the issue since late last month and underwent a procedure to address the condition shortly after his diagnosis. He returned to the team on Sept. 14 to participate in light exercise, at which point Lagerwey said he was “cautiously optimistic” about Dempsey’s return to game action this season.

But Dempsey stopped training with the club last week before his season officially ended on Tuesday. No additional information is available on whether the condition could potentially end Dempsey’s career.

The Sounders, meanwhile, have gone 2-1-1 since Dempsey’s diagnosis and will return to action at home against the Chicago Fire on Wednesday (7:30 p.m.; JoeTV/KIRO 97.3 FM/El Rey 1360 AM).

Dempsey is the USMNT’s second all-time leading goalscorer and joined the Sounders as a Designated Player in August 2013. He has 34 career goals for Seattle in 72 matches over three-plus seasons, including eight tallies this year.

The news Tuesday will certainly affect Dempsey's availability for the U.S. national team’s upcoming friendlies against Cuba and New Zealand next month and potentially the team’s World Cup qualifying matches against Mexico and Costa Rica in November.