United States striker Clint Dempsey is being tested for an irregular heartbeat and will miss the Seattle Sounders' game on Sunday against the rival Portland Timbers as well as upcoming World Cup qualifiers.
The Sounders announced on Friday that the 33-year-old would be held out of the game at Providence Park (5 p.m. ET, ESPN).
Dempsey was rested for the Sounders' midweek game against the Houston Dynamo on Wednesday, but the club said that decision was made separately from concerns related to his heart.
"As the medical process unfolds and information is gathered internally, no other details are being made publicly available at this time," the team statement said.
A U.S. Soccer spokesperson confirmed to ESPN FC that Dempsey will not be called in to the national team for the World Cup qualifiers at Saint Vincent and the Grenadines on Sept. 2 and against Trinidad and Tobago four days later.
Seattle general manager Garth Lagerwey said a timetable on Dempsey's potential return won't be known until all the evaluations are complete. He said the irregular heartbeat is something the team has been monitoring during the season and the club is now waiting on the recommendations of doctors on how to proceed.
"Everybody here -- us, U.S. Soccer, Clint -- we're all on the same page,'' Lagerwey said at practice on Friday. "Let's get to the bottom of this, let's see what's going on and let's do what's best for Clint.
"Clint has given a great service to this club and we owe him an equal measure of respect and support as we go through this medical evaluation."
U.S. Soccer president Sunil Gulati wrote later on Twitter that he had spoken to Dempsey:
Spoke with @clint_dempsey today. He's in great spirits and appreciates everyone's support. #OneNationOneTeam
- Sunil Gulati (@sunilgulati) August 26, 2016
Dempsey has scored eight goals for the Sounders this season, five of which have come in Seattle's recent resurgence since the firing of longtime coach Sigi Schmid.
"All our thoughts go out to him and his health. He's got a family so his health is No. 1," Sounders interim coach Brian Schmetzer said. "He wants the team to do well on Sunday. From there, I'm not a doctor and I don't know the rest of the timeline.
"I'm focused on Sunday and then we'll have a little break to get our arms around things and figure out exactly what's going on."