The 17-time major champion contemplated both scenarios, holding out hope as long as he could that he'd find a way to enter at least one of the big events in August.
In the end, his balky left knee wouldn't allow him to do either.
At a meeting with doctors and trainers, Federer recalled, ''Everybody said, `You need a break - right now.'''
So the Swiss great announced in late July that he'd miss the rest of the season, by far the longest layoff of a remarkably healthy career.
Federer, who turned 35 this month, was in Manhattan on Wednesday to talk about playing tennis next year at the new Laver Cup team event. But for the first time since 1999, he's not preparing for the U.S. Open.
He underwent an arthroscopic procedure in February to repair torn cartilage - the first surgery of his career. Federer hasn't played since his Wimbledon loss to Milos Raonic, in which he fell awkwardly and called the trainer to check on what had become a nagging knee problem.
''I never really had pain, funny enough,'' Federer said Wednesday. ''It just felt unstable.''
Then there was the swelling.
''When it's swollen, you can't compete at the best level,'' he added.
An MRI didn't show anything distinctly different from before. For all his upbeat talk Wednesday about his future, Federer let some doubts seep in when he discussed the mystery of what's going on in the knee.
''That's why, I think, it's been to some extent frustrating,'' he said. ''At least if I had a lot of pain, or if the scan shows you thoroughly what exactly the problem is, then I think it's easier to take a decision.
''I really hope I'm not being misled by the knee that it doesn't feel painful. But it's just not 100 percent. That's why I just think the beating that I got in Wimbledon and the clay court season was just so complicated.''
Federer, who also skipped the French Open because of a bad back, didn't play tennis for five or six weeks and just now is starting to do a few things on the court. He's focused on exercises to strengthen his left quadriceps, such as squats, so he'll be physically ready once he ramps back up to his full workouts to prepare for January's Australian Open.
It might have been possible to return for a couple of tournaments late in 2016, Federer said, but there was no point once he knew he would miss the bulk of the fall schedule.
He reflected back to this past January, when the Laver Cup concept was unveiled at the Australian Open, and marveled: ''My God, I never thought I was going to have a year the way I had it.''
He hurt his knee while preparing a bath for his twin daughters, then later saw his record 65-appearance streak at major tournaments end. Federer won't win a title in a season for the first time since 2000. And now that he missed the Rio Games, his career could end without an Olympic singles gold medal.
He insisted he hasn't missed competition yet, though maybe that will change when the U.S. Open starts next week. The quiet away from the spotlight has been nice, he said - even if he quickly amended that to: ''I've got four kids - it's a different quiet.''
Back in New York, site of five of his titles, Federer said he watched a lot of volleyball during the Olympics and spoke to Andy Murray after the Brit won gold. Despite Murray's recent run, Federer still believes Novak Djokovic is the favorite at the U.S. Open.
No matter that the world's top-ranked player has struggled by his standards since completing the career Grand Slam at Roland Garros - Djokovic is just too good on the hard courts and too successful against Murray, Federer said.
If the Serb does win to move within four major titles of Federer's record, the man he's chasing will be forced to watch from afar.
''In a way it's painful, just because I love this place,'' Federer said, ''and it's hard watching the Olympics - I would have loved to have competed there as well. ... Would have loved to win a medal.''