Roger Federer admits his knee injury is part of the reason he is skipping most of the clay-court season.
The 18-time grand-slam champion continued his incredible start to the year by clinching the Miami Open with a 6-3 6-4 win over Rafael Nadal in the final on Sunday.
Federer, 35, later announced the only clay-court event he was likely to play in 2017 was the French Open in May-June.
The Swiss star missed a large part of last year due to knee surgery and said that was part of the decision to stay off clay.
"All the grass is important to me," Federer said, via The Telegraph.
"The second part of the season is the big priority. It's more about relaxing right now, more about injury prevention.
"My knee was strange on the clay last year and my physio thought that was a good thing: not playing too much on the clay."
Federer has enjoyed an amazing start to 2017, holding a 19-1 win-loss record that includes titles at the Australian Open, Indian Wells and Miami.
But he felt the scoreline in the Miami decider was unfair on Nadal, his great Spanish rival he has beaten four consecutive times.
Federer said: "I think it was a close match. Maybe if you didn't see the match and you were sitting somewhere around the world and you see the score you're thinking it was straightforward with couple breaks and that was it.
"That's not the full story. I thought he had his chances in the first and in the second. It was close. I think on the big points I was just a little bit better. Why? I have no explanation. I just think it fell that way.
"It was more of a fight mode I was in just trying to stay afloat. Physically, emotionally it's been a draining week, so I did very well."