Croatia captain Zeljko Krajan sprang a surprise at the draw in Umag by naming 16-year-old Borna Coric as his second singles player. The teenager, who has a British coach and trains part-time in London, is up against the reigning Wimbledon champion in his first best-of-five-sets match.
Coric is regarded as one of the sport's brightest young talents and last weekend won the junior title at the US Open, nine years after Murray lifted the same trophy.
"I haven't seen Coric play before but plenty of our guys have," said Murray. "He's very young and is very inexperienced at this level but I'll be ready for him."
For the Scot, it will be a good chance to get the US Open out of his system a week after his disappointing quarter-final defeat by Stanislas Wawrinka. As expected, Dan Evans was picked to back him up by captain Leon Smith following his terrific run to the third round in New York. The 23-year-old is at a new career-high ranking of 149 and will play Friday's second singles rubber against Croatian first-choice player Ivan Dodig, who is ranked 35th.
Smith had picked both Evans and British No.3 James Ward in his original team, but, having assessed both on clay in Umag this week, Smith has given Evans the nod and made a change to his four-man team, with Jonny Marray replacing Ward.
Evans said: "We've practised a lot all week and the banter's been fun. The turnaround after the US Open was very quick so I haven't had time to think about what happened there."