Roger Federer feels like he is heading into the unknown as he prepares to make his first French Open appearance since 2015
Federer, who will face Lorenzo Sonego in the first round and is in the same half of the draw as 11-time champion Rafael Nadal, skipped the past three editions of the major to focus on grass and hard courts.
Having started 2019 with a disappointing performance in the Australian Open - losing to youngster Stefanos Tsitsipas in the fourth round – the Swiss' form has improved, winning titles in Dubai and Miami either side of losing to Dominic Thiem in the Indian Wells Masters final.
The 37-year-old withdrew from the Internazionali d'Italia due to a right leg injury, though he confirmed the decision was precautionary after rain delays forced him to play two matches in a day.
Federer likened the situation to when he headed to Melbourne Park in 2017, having not played since Wimbledon the previous year due to a knee problem.
"It's a bit of a question mark for me," Federer told a news conference on Friday.
"In some ways I feel similar to the Australian Open in 2017 – a bit of the unknown. I had no expectations.
"I'm just happy to be back in good health. It's more or less the same, and I know that my first opponent will be someone who knows how to play on the clay.
"I feel like I'm playing good tennis, but is it enough against the absolute top guys when it really comes to the crunch? I'm not sure if it's in my racket.
"But I hope I can get myself in that position deep down in the tournament against the top guys. But first I need to get there and I know that's a challenge in itself.
"It's definitely going to be an exciting tournament mentally to go through."
The world number three is confident his body can hold up to the rigours of 2019's second major.
"I think I have been able to train hard enough and also got the necessary tough matches in Madrid and Rome, more than I would have liked to, but I guess we like saving match points or trying to lose with match points," Federer said.
"But no, I really feel like playing under the pressure and playing with the nerves was important for me, so I feel totally ready.
"In any grand slam of course if you can avoid tough, long matches in the beginning, it's going to increase your chances for the tournament later on.
"But I just want to get through that first round to get the campaign going. That's my focus right now, not think too far ahead."