Isner, ranked No. 13, retired from his first-round match at the Australian Open because of an injured right ankle. Joining him on the American roster announced Monday by U.S. captain Jim Courier are Sam Querrey and the doubles team of twins Bob and Mike Bryan.
Murray is ranked No. 4 and was selected by British captain Leon Smith on Tuesday, along with Kyle Edmund, James Ward and doubles specialist Colin Fleming. Murray may be asked to play singles and doubles.
The best-of-five matches are Jan. 31-Feb. 2 and will be played on a clay court set up in left field of the ballpark.
Britain and the U.S. played the first Davis Cup match in 1900. They have met 18 times, with the Americans leading 11-7.