The Seattle Sounders are in the midst of the best start to a season in their MLS history, but their drive to keep it rolling could be complicated by a pair of injury updates to two of their best players, which were announced by head coach Brian Schmetzer on his Friday video call with reporters.

Schmetzer led off his availability with the news that star playmaker Nicolas Lodeiro and stalwart goalkeeper Stefan Frei have each endured setbacks on their respective injuries that will keep them off the field for longer than initially anticipated. Lodeiro has undergone arthroscopic surgery to relieve inflammation in his knee, while Frei developed a blood clot in his sprained knee that he injured in Seattle's 1-0 victory over the San Jose Earthquakes on May 12.

Both players were already ruled out through the upcoming June international break, but Schmetzer said on Friday that the new developments will keep them out for additional time after the league resumes play. While the exact timelines for return are unclear, Schmetzer did say the hope is that they'll be back during the 2021 season.

"Nico Lodeiro had arthroscopic surgery yesterday to deal with his lingering inflammation in his knee joint. It was a successful surgery, everything went well, Nico's doing great," Schmetzer said. "That's number one. Number two, regarding Stef's injury, he had a complication because of the injury he suffered against San Jose and he actually developed a blood clot, and so what happened is we're going to be very careful. It's obviously a little bit more serious than just a sprained knee.

"We've always been good as a club to make sure we take care of our players, that is our number one concern right now, so he will be out for an undetermined amount of time as the doctors work through the procedures to get him back on the field. But with both players we do expect them to get back for parts of the regular season, and we'll keep you guys updated as far as those timelines as needed."

Lodeiro has only made one substitute appearance for Seattle this season before he was shut back down, with the club still managing to rattle off a blistering start in his absence, as the Sounders currently reside atop the league table with a 5-0-2 record and 17 points from seven matches.

Cristian Roldan has moved up the field to fill in at Lodeiro's center attacking midfield spot to positive returns so far, while backup goalkeeper Stefan Cleveland has also fared well in his two games in Frei's place. Both players figure to remain as the first-choice fill-ins.

"It's not going to be in the next 2-3 weeks, right after the break," Schmetzer said of Lodeiro. "That's one of the benefits of having a good start, [we won't] rush him along. I'm going to make sure this injury gets settled so it doesn't come back. So we'll be cautious with the rehab and just make sure when he's ready he's totally ready. With Stef, there's no concrete timeline there, we'll just keep you updated."

As for his team's approach moving forward, Schmetzer reiterated that he doesn't feel the need to make any drastic changes to a formula that has been working so far. More broadly speaking, the coach did say that the club figures to have its eye on some summer reinforcements in the form of new signings, but qualified that probably would have been the case irrespective of the injury situation.

The Sounders take the field next with a home matchup against expansion side Austin FC at Lumen Field on Sunday (9:30 pm ET | FS1, FOX Deportes).

"Look, we were always geared up to try and add pieces in the summer, I think that hasn't changed," Schmetzer said. "Again, we haven't had Nico and he's a big part of our team, but I think guys have stepped up. And so, I'm not going to change the formation, I mean, our formation's working. So, both of those questions I can definitely say we're not going to change anything, we're still going to go out try and win games and be as good as we can in our new formation and then Garth [Lagerwey] and Craig [Waibel], all the scouts, they're working on potential targets for the summer."