The 22-year-old was initially given a six-to-eight-week timeframe for his recovery from a knee injury which put his participation in Qatar in doubt.
However, those around the defender have grown increasingly optimistic that he can make the showpiece event and Potter hinted that he could be back soon.
“No miracles, unfortunately,” the Chelsea boss said at Cobham on Tuesday. “He’s progressing well. Reece was outside today, had a little jog, but nothing to report in terms of anything else.
“We haven’t really put a timescale on it. It’s just how he responds, we don’t want to rush anything. I certainly don’t want to put any timescales on it, that’s for him and the doctors and the physios. He’s optimistic, you need to be.”
It doesn’t help the Blues for their upcoming away trip to the Etihad Stadium to face Manchester City in the Carabao Cup. They have seven players out after Jorginho joined the injury list alongside Kepa, James, N’Golo Kante, Wesley Fofana, Ben Chilwell and Carney Chukwuemeka.
Potter said: “Jorginho has a slight problem with his foot, doubtful for tomorrow. Other than that, pretty much the same group.”
Mateo Kovacic is also managing a minor knee problem. Potter added: “He’s just had an ongoing knee issue that’s a little bit of discomfort, but it hasn’t stopped him completely.
“Certainly we’ve had to be conscious of that fact during this period. It’s not a massive problem for him, he’ll be fine for the World Cup, it’s fine.
“I wouldn’t say he’s necessarily 100 per cent but he’s not far away from that. It’s just that we’ve managed it really well and he’s managed it really well.
“He’s a top professional, he’s done everything he can in terms of rehab and looking after himself in the gym, making sure his body’s as good as it can be.
“He’s a fantastic professional, but I think it’s been going on pretty much from pre-season and we’ve tried to make the best of it.”
Such a lengthy injury list has left Chelsea needing to call up talented academy stars Omari Hutchinson and Lewis Hall for the trip to City.
“Hutchinson in the squad, Lewis Hall is in the squad. They’ve impressed,” Potter said. “We’ve got some good quality young players. They’ll be in the squad and involved.”