Murray's fitness has become a major issue ahead of the start of Wimbledon on Monday after the Scot was forced to pull out of two grass-court exhibition matches at the Hurlingham Club this week.
The two-time Wimbledon winner withdrew from facing Lucas Pouille on Tuesday due to his sore hip, then opted not to take part in his scheduled practice session on Wednesday.
On Thursday, Murray revealed he wouldn't play his second exhibition on Friday because he wanted to continue resting his hip.
With Wimbledon just days away, Murray's fitness woes have sparked fears he might miss the tournament.
But as the defending champion, Murray has the honour of opening proceedings on Wimbledon's Centre Court next week and Federer believes the 30-year-old will be there for the start of the tournament.
"We're talking like he's in hospital almost. It seems like he can't walk no more," Federer told reporters at a Laver Cup launch in Wimbledon on Thursday.
"The way I know Andy, he is tough as nails. I feel like he will be there on opening Monday.
"There are injuries and injuries. He would have to be seriously injured not to play.
"For me if he can be get through the first round and feel better after he should play. I expect him to play."
While Federer is confident top seed Murray will be ready to feature at the All England Club, the seven-time Wimbledon champion acknowledged it would be foolish to play if he doesn't believe he is fit enough to make it through the gruelling two-week tournament.
"You would need to feel like you could play for 14 days, if you feel you can only play one match it isn't good enough," Federer said.
"Going over the best-of-five sets over two weeks, only the tough ones will survive, it will flush you out.
"You need to feel confident in your body otherwise what's the point.
"The world is watching, the defending champion opening the court is a big deal.
"Because it's a big deal you want to feel as close to 100 percent as possible."
- 'Absolutely amazed' -
Even if Murray is fit enough to play, he goes into Wimbledon desperately short of time on grass after suffering a shock Queen's Club first-round defeat against Australian world number 90 Jordan Thompson.
But Federer says Murray is experienced enough on grass to be able to quickly adapt to the unique demands on the surface.
"Yes sure, it's ideal is to win everything beforehand and to feel great in practice, but the most important thing for him is to get through the first week," Federer said.
"He is a great first week player. He doesn't mind the slippery grass, he doesn't mind the bounce of the ball. He might even thrive in these conditions.
"I'm not happy to hear he is struggling with something. I hope it's not serious. I wish him the best."
American great John McEnroe, another former Wimbledon champion, agrees with Federer that it would take a serious injury to keep Murray from appearing.
Rafael Nadal was the last male Wimbledon champion to miss out on defending his title back in 2009.
"Everyone knows how nice that tradition is. I'm sure it killed Rafa," McEnroe said.
"I would be absolutely amazed if Andy didn't do it.
"That would definitely tell you it's a serious injury and he would be out for a serious length of time."