MELBOURNE, Australia -- U.S. Davis Cup captain Jim Courier has selected teenager Ryan Harrison to the four-man squad that will play Switzerland next month in the first round.
Bob Bryan is missing the match because his wife is due to have a baby, so Courier says Fish and Mike Bryan are the likely doubles pairing, with Fish and Isner playing singles.
Andy Roddick had already decided not to play before he was injured during the Australian Open.
"Honestly it's unlikely that the third singles player is likely to play," Courier said. "But we need someone and Sam Querrey's knee is not quite right. Ryan is healthy, hungry and he's eager."
Switzerland's team is likely to be led by 16-time Grand Slam champion Roger Federer.
"We're honored," Courier said. "We have about the toughest draw you can have. It's going to be a battle for our guys but we have nothing to lose. We've got to go out there and lay it on the line. We know we're the underdogs, why not give it a rip?"
The No. 3-ranked Federer is set to be supported by No. 22 Stanislas Wawrinka.
At No. 8, Fish is the top-ranked American player but he had a disappointing Australian Open, losing in the second round to Alejandro Falla.
"Mardy is excited," Courier said. "It's a chance for him to get back on the horse quickly. He loves Davis Cup, there's nothing he'd rather be involved in. He didn't have a great Aussie summer, he knows that, and he wants to go back out and play like the player he's been the last couple of years."
Courier is hopeful that former No. 1-ranked Roddick, who has a 33-12 record in Davis Cup and has been the mainstay of the team for several years, will make himself available later in the year.
"What I wanted from him and what we have from him is a commitment not to close the door," Courier said. "He should have the freedom to come and go as he pleases as far as availability and we'd love to him back on the team."
Despite being underdogs this time around, the U.S. takes a 3-0 record into the match against Switzerland.
The teams first met in the 1992 final at Fort Worth, Texas, when a powerful lineup of Courier, Andre Agassi, Pete Sampras and John McEnroe combined for the U.S.
After the opening day singles were split, Switzerland pair Jakob Hlasek and Marc Rosset took a two-set lead in the doubles against McEnroe and Sampras.
Courier said the match provided one of the most memorable moments of his Davis Cup career after the third set.
"I'll never forget being in the locker room and Mac just being in Pete's face and getting him fired up and we won," he said. "I don't remember word by word but he was in his face, yelling, fist pumping. He was definitely taking charge of the situation, it was kind of wild to see."