Bristol City boss Steve Coppell admits he is concerned about Wales defensive pair James Wilson and Christian Ribeiro as they battle to recover from injury.
Coppell found himself without the services of five players as his new charges returned for pre-season training this week.
Marlon Jackson, Jamie McAllister and Louis Carey are short-term absentees but Wilson and Ribeiro are nursing knee and back problems respectively.
Coppell told the club's official website: "Christian's going to out for a while (with the back injury). He's had it before but I think it was exasperated by playing for Wales when he perhaps shouldn't have done.
"With back problems you have to just let them heal at their own pace. I had a back problem last year and it took time to shake off.
"James has a knee problem and tendon issues are also difficult to shift. We're making sure that once it goes away, it goes away for good. We don't want to force anything and make the injury reoccur. They are both good players with bright futures so we're erring on the side of caution."