Scotland duo Finn Russell and Cameron Redpath are facing lay-offs after sustaining what Bath describe as “significant” injuries.
Both players were withdrawn during the 21-15 Champions Cup defeat at Exeter on 6 April.
Scotland co-captain Russell, 31, has a groin problem while centre Redpath, 24, has damaged ankle ligaments.
Bath head of medical Rory Murray did not give a recovery timeframe for either player when announcing the news.
He did say the duo would be “assessed weekly”, with head of rugby Johann van Graan explaining: “The reason why we say weekly is it is too difficult to put a specific timeline on.
“We will make that decision as every week goes by and hopefully we will see them back sooner rather than later.”
Referring to fly-half Russell, Van Graan added: “The injury is what we call significant, so what we mean by that it is not something that he will quickly run off in five or six days.”
Bath are second in the Premiership with four regular-season games left as they target the play-offs, and ultimately the final in early June.
Scotland play Tests against Canada, the United States, Chile and Uruguay in July.
Russell, capped 80 times, is unlikely to be considered for such a tour, with head coach Gregor Townsend saying he would use a “wider group of players” when the dates were announced last month.
Redpath has made four starts in 14 appearances for Scotland, only featuring sporadically during this year’s Six Nations, so may well be in Townsend’s thoughts for the summer.