World number three Andy Roddick has fired his coach Dean Goldfine and hired his older brother John to replace him.
"I felt like I needed something fresh. It was more of a mutual decision between Dean and I," Roddick told reporters on Thursday, the day before he leads the U.S. team into a Davis Cup tie against Romania.
"It was getting a little stagnant. I don't know if I was doing justice to the level of Dean's coaching. We both needed to cut our losses."
John Roddick will be his brother's fourth coach since he joined the tour in 2000.
Roddick parted company with French Davis Cup player Tarik Benhabiles in 2003 and hired Brad Gilbert, who took him to the U.S. Open title and top of the world rankings.
After a five-month slump at the end of 2004, however, Roddick fired Gilbert and took on Goldfine, who had been a Davis Cup coach.
Roddick won five tournaments last year and reached the Wimbledon final, where he lost to Roger Federer.
But his shock first-round U.S. Open defeat by Gilles Muller of Luxembourg and loss to Marcos Baghdatis of Cyprus in last month's Australian Open left Roddick looking for a new direction.
A former top collegiate player, John Roddick also coaches Ryan Sweeting of the Bahamas, the U.S. Open junior champion.
"John knows Andy as well as anyone," said U.S. Davis Cup captain Patrick McEnroe.
"He's never stopped following his game and won't be afraid to criticise Andy if he sees something going wrong. Maybe Andy needs some of that. He gets pissed off at me sometimes, too, but he willing to listen and it's a good sign. He really respects John."
