Roger Federer may not be 100% fit ahead of the Rotterdam Open final, according to former world number eight Peter Fleming.

Federer defeated Andreas Seppi on Saturday (17 February) in straight sets, 6-3, 7-6, to meet Grigor Dimitrov in the final as the newly crowned world number one already looks to win a second title of the year.

However, while commenting on the game for Sky Sports, Fleming observed that the 36-year-old's is not moving as well as he did last year.

"As good as Federer is feeling, I don't know if he's moving as well as I expected," Fleming said, as per Express. "I wonder if he is really feeling 100 percent physically.

"He's moving great, don't get me wrong. But last year when he was taken out wide to the forehand he would slide out wide to that ball and still get over it.

"He doesn't seem to want to make such an ambitious move at this point."

The Swiss legend notably returned from a long injury layoff to experience a career resurgence in 2017 as he won a total of seven titles including the Australian Open and a record-breaking eighth Wimbledon crown.

But despite a remarkable year, Federer was not injury-free throughout the season as he was plagued with a back issue during the hard-court season. It was his withdrawal from the Paris Masters for "injury prevention" that ultimately saw Rafael Nadal overtake him to become the year-end world number one.

The 20-time Grand Slam winner, though, did not mention any fitness or injury problems when speaking in an interview with the ATP World Tour website following his win over Seppi, as he was looking forward to facing Dimitrov on Sunday (18 February).

"I enjoy playing against Grigor, I feel like I know how he feels as a one-handed backhand player with a big serve, big forehand," Federer explained.

"I'm going to have to play aggressive, play my game and then hope for the best but I hope I have a good serving game, that will be helpful."