The Swiss went under the knife to repair a torn meniscus after he suffered the injury at the Australian Open back in January.
The 34-year-old withdrew from the Indian Wells Masters, which is taking place this week.
But Federer’s fans will be pleased to see that the world No3 is back in training as he bids to return to full fitness as quickly as possible.
Federer posted the picture above on his personal Instagram account on Monday and wrote: “Rise and grind.”
Over the weekend, the Swiss star shared the picture below and added: “Warming up before playing #tennis”
MORE: The latest tennis news