Sean Dyche says Dominic Calvert-Lewin will not be available for Everton's clash with Leeds United on Saturday afternoon (3pm GMT).
A hamstring concern meant the striker was withdrawn after an hour in the 1-0 win against Arsenal two weeks ago and he was an omission for Monday night's Merseyside derby.
Dyche revealed the 25-year-old is still not available for selection and will need "time".
“The root of the problem is pretty easy from a medical side of things," he explained in Friday's press conference held at Finch Farm. "Now it’s just a case of time.
"While he's out, we want him to do work to strengthen the whole body, not just the injured site.
"That's the process to go through for a player being injured and getting them back on the pitch when they're fully fit and clear. But then they will still need some training days.
"Because when you train under control with physios, it's a different type of training. But when you train with the first team, it's reactive. You have to react and be proactive.
"You can control different ways of coming back from injuries, when bodies are free and clear, getting that natural movement pattern. That can take a bit of time. He [Dom] hasn't been out that long, so you'd hope that would happen quite quickly."
The boss also provided updates on James Garner and Nathan Patterson, with both edging closer to a return and set to feature for Paul Tait's Under-21 side tomorrow night.
"A couple of the lads will play tomorrow, which I am going to watch," said Dyche.
"Jimmy will play tomorrow, and Pato (Nathan Patterson) will play as well. So I will get over and watch them for the first time.
"They are not there yet, but they have been on the grass with us. Next is to put it into game practice."
Andros Townsend (ACL) remains unavailable.
You can watch Everton Under-21s in Premier League 2 action on Friday evening (7pm GMT) on our official YouTube channel!
Our coverage of Friday's game against Tottenham begins just before kick-off. Watch via the player below or on YouTube here.