Roger Federer must 'play as many matches on clay as possible' to prepare for Wimbledon, says Marc Rossett.
Rossett, a former Swiss Olympic gold medallist, is close to Federer, and he believes his compatriot was maybe a little surprised at his lack of fitness in his recent comeback in Doha.
Federer beat Dan Evans in Qatar before losing to Nikoloz Basilashvili, with both matches going to three sets and the 39-year-old tiring badly.
"Roger Federer saw that maybe he was lacking a bit of physical preparation," Rosset told L'Equipe.
"So I think it's going to be interesting for him to really play as many matches as possible on clay."
"[Playing on clay] will allow him to do a little land work, to get a bit of a physical shape."
Rossett also believes substantial clay court tennis could help Federer at Wimbledon, as the serve-volley days of SW19 appear to be on the wane, and it will also allow him to get a reading on his main rivals.
"Wimbledon is hardly won anymore by serving-and-volleying, it is won from the baseline," Rosset said.
"If he also wants to win Wimbledon, he will necessarily have to beat Djokovic, Nadal or other players who are in the top 10.
"And to meet them [beforehand], he will have to play these players in the Masters 1000 on clay or at Roland Garros."
For more exclusive content from Tennisbuzz, including news, features, trivia, promotions and more, please be sure to sign up for our newsletter below or via our home page.
Why not test your tennis knowledge by tackling one of our fiendish quizzes too?