Great Britain's Davis Cup captain Leon Smith has said that the team will wait on Andy Murray's fitness ahead of the doubles rubber tomorrow afternoon.
The Wimbledon champion, who has been struggling with a recurring back complaint, beat teenager Borna Coric in straight sets during the singles matches in GB's World Group playoff against Croatia.
Smith told BBC Sport: "The doubles isn't until the afternoon so it give us plenty of time to assess it. Andy has been feeling his back, it's an ongoing issue. He has good people around him and will get lots of treatment.
"The welfare of Andy's body is far more important than this tie and we have a former Wimbledon champion who is waiting to come in should Andy not be able to play. It's not a bad situation to be in."
Should the Scot be unable to play, then 2012 Wimbledon men's doubles champion Jonathan Marray will partner Colin Fleming.