MADRID, Spain — Injured doubles player Bob Bryan has been replaced on the U.S. team by Mardy Fish for the Davis Cup semifinal against Spain this weekend, the second high-profile loss for the American side.

Bryan is recovering in the U.S. after receiving a cortisone shot for an inflamed left shoulder, team spokesman Tim Curry said Tuesday. Singles player James Blake, who has been a regular on the U.S. team since 2005, pulled out last week citing exhaustion.

It will be the first time in 16 Davis Cup matches that Bryan and his twin brother, Mike, won't play together. The Bryans, who are 14-2 since debuting in 2003, helped the U.S. win the Davis Cup last year.

"I aggravated it pretty bad at the (U.S.) Open and only made things worse," Bryan said on the Davis Cup Web site. "I knew if I wanted a chance to play the rest of this year, I had to shut it down now. I can't even hit any balls."

The 23rd-ranked Fish practiced on the clay Tuesday with Mike Bryan and could line up with him in doubles. The other team members are Andy Roddick and Sam Querrey, who replaced Blake.

"When you have a pair like the Bryans that know each other well ... a match against them is always difficult," Spain captain Emilio Sanchez Vicario said. "But Fish reached the quarters of Australian and U.S. Open and comes with talent even if he doesn't play doubles in a consistent fashion."

The best-of-five series begins Friday with two singles matches, followed by the doubles on Saturday and reverse singles Sunday. The matches will be played on red clay at the Las Ventas bullfighting arena.

The Spanish team is led by No. 1-ranked Rafael Nadal.

Fish is 5-5 in Davis Cup play, including 4-4 in singles and 1-1 in doubles. His last appearance was in 2004, when he won one singles match and lost another as Spain beat the U.S. in the final in Seville.

Though Spain appears the overwhelming favorite now, Sanchez Vicario said the team was doing some adjusting of its own to the Spanish capital's high altitude.

"The altitude is something that influences the game very much, but we feel positive here and we will look to play the best we can," he said. "We came here early to accustom ourselves to it."