The 23-year-old was stretchered off in the 65th minute of the UEFA EURO 2016 winners’ 1-0 victory in Moscow and could now miss the start of the 2017/18 season.
Borussia Dortmund confirmed on Twitter that, according to the medical team of Portugal, Guerreiro had suffered only bruising to his ankle. Earlier reports had suggested that the versatile youngster had fractured his ankle.
Portugal head coach Fernando Santos had told the assembled media after the match that they had suspected his ankle was broken. "It’s very sad, he’s a fantastic lad and a great player," Santos said.
Guerreiro has made 35 appearances in all competitions for BVB since joining the club from FC Lorient last summer, scoring seven and setting up a further ten goals.
Watch: Relive Guerreiro's stunner against Bayern Munich on Matchday 28 of the 2016/17 season