Chelsea manager Thomas Tuchel told media on Friday that American winger Christian Pulisic has tested positive for COVID-19.
Pulisic will not be available for the Blues' game on Sunday against Arsenal. He started Chelsea's season-opening 3-0 win over Crystal Palace last Saturday.
The 22-year-old was in and out of Tuchel's starting lineups since the German coach took over Chelsea in January, so there's unlikely to be any significant movement on the betting market for the London derby on Sunday.
The real implications for bettors would be when the United States men's national team opens World Cup qualifying in early September.
The Americans have three games in six days, including a pair of trips to Central America for matchups against El Salvador (Sept. 2) and Honduras (Sept. 8). Between those is a Sept. 5 matchup against Canada in Nashville.
This news does rule Pulisic out of two important away fixtures for Chelsea, the match against Arsenal and then an Aug. 28 trip to Anfield to face Liverpool.
Chelsea isn't the only Premier League club that has been affected by COVID-19 early in the season. Arsenal had strikers Pierre-Emerick Aubameyang and Alexandre Lacazette, winger Willian and goalkeeper Alex Runarsson ruled out of their season-opening loss to Brentford due to positive tests. Only Aubameyang has tested negative and is in contention to face Chelsea.
COVID-19 could continue to be an issue this season in the Premier League. Newcastle United manager Steve Bruce told the media before his team's Saturday matchup against Aston Villa that "a lot" of his players have not gotten their vaccinations yet.