Roger Federer is skipping the Miami Open to do a 'training block' to assess how his knee stands up to his Doha comeback, says his agent.
Federer has not played for over a year after needing two operations to correct a long-standing knee issue.
He is in Doha now, though, preparing to return to competition next week, although there was disappointment when it emerged he had withdrawn from Miami at the end of March.
However, Federer's agent, Mike Godsick, says it is simply part of the Swiss star 'slowly' getting himself back up to speed.
"After Doha and maybe Dubai, [Federer] will go back and do a training block to continue to slowly work his way back out on tour," Godsick said.
Federer's absence is sure to be a blow for Miami, who were hoping to reunite the big three at the same tournament for the first time in over year.
Tournament director James Blake, though, says he fully understands the decision.
"We certainly would have loved Roger to return to Miami to defend his title," Blake said.
"However, as a former player, I understand that you need to tailor your travel and playing schedule to properly work your way back to 100 percent fitness when coming off an injury
"Roger is an incredible ambassador for the sport, so the longer he is able to play on tour, the better it is for all of tennis."
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