Millwall boss Neil Harris expects Fred Onyedinma to put pen-to-paper on a new long-term contract with the club early next week.
Talks have been ongoing for some time, but positive progress was made between both parties on Friday.
Onyedinma started Saturday's 1-1 pre-season friendly at Dartford and Harris confirmed reports that the Academy graduate was set to sign.
"It's really good news for the club," he said. "Talks have gone on for longer than we would have hoped, but throughout the entire process, Fred has shown a real desire to be at this football club.
"He sees his long-term future at Millwall and we are confident that if he continues to work as hard as always has done, then he can continue to improve as a player and make a significant impact on the pitch for us."
Ben Thompson scored a second-half equaliser as The Lions drew 1-1 with The Darts in their first pre-season friendly and Harris admitted that his side will get better as the opening game of the 2017/18 Championship season approaches.
"The boys have had a very, very tough week of training and I think that showed at times," he added.
"Our combination play wasn't quite there across the park and it was a very typical opening pre-season friendly type of performance.
"Performances will get better as we keep working through pre-season and shaking off that rustiness.
"What is key at this stage is that we get through each hurdle without any injuries and it looks like that has been the case today, so overall I'm pleased."