Bryan was part of the lineup Courier selected Tuesday for the matches in Croatia from Sept. 14-16.
John Isner, playing in the U.S. Open quarterfinals, won’t travel with the Americans because his wife is due to give birth to the couple’s first child this month.
“There’s no question that John would have been valuable for us if he was available, but to miss the birth of your first child would not be a good lifetime decision,” Courier said.
The rest of the U.S. roster includes Jack Sock, Sam Querrey, Steve Johnson and rookie Frances Tiafoe.
Mike and Bob Bryan retired from Davis Cup competition in 2016 after a 24-5 record. Mike won two other matches without his twin brother and is the Americans’ career leader in Davis Cup doubles victories.
Bob injured his hip earlier this year and Mike has since been teaming with Sock, winning the Wimbledon title. So Courier asked Bob if he would be OK with his brother returning to action to play without him, calling it a sensitive subject.
“They retired from Davis Cup tennis as one of the most storied doubles teams for any country, let alone what they’ve done for us,” Courier said. “And it was a delicate scenario and I knew that Jack and Mike would be our best option, but I wanted to make sure that they had Bob’s blessing out of respect for what they mean to our team.”
The 20-year-old Tiafoe is the youngest player nominated to a U.S. Davis Cup team since Ryan Harrison was 17 in 2010.
The matches will be played on an outdoor clay court in Zadar.
Croatia, led by 2014 U.S. Open champion Marin Cilic and 21-year-old Borna Coric, is 4-0 against the U.S. — the only country the Americans have never beaten.
Spain and France meet in the other semifinal.
By BRIAN MAHONEY, Associated Press