During an interview with NFL Network's Steve Wyche, Demoff provided an update for where things stand in negotiations between the Rams and Donald.
"Well, it will be done before the stadium's done," he said. "Nah, we're going to keep wishing and hoping. I hope it's done sooner than training camp, but if it goes to training camp, our goal is to make sure it's done and that he feels rewarded and that it's a win-win deal for both sides."
Demoff also described the contract discussions as "great" and "positive," adding Donald has a good relationship with head coach Sean McVay.
Donald will earn $6.8 million in 2018 before becoming an unrestricted free agent.
He held out of the team's offseason activities in 2017, eventually reporting to team facilities in September. He appears to be taking the same approach this summer, having already skipped Los Angeles' minicamp earlier in the month.
Rams veterans are expected to report for training camp July 25.
Donald's performance didn't suffer last season despite his lengthy absence during the preseason. He finished with 41 combined tackles and 11 sacks, tying a career high. He was also a first-team All-Pro for the third straight season.
Donald is going to get paid one way or the other in 2019; the big question is whether he'll receive a long-term extension or get the franchise tag.
The Ringer's Robert Mays estimated being tagged for three years would potentially net Donald $58.7 million. Mays argued, however, going that route could potentially alienate Donald and some of his teammates, since the Rams could come off as wanting to save money rather than reward Donald for his work.
Should Donald and Los Angeles fail to reach an agreement on a new deal before next offseason, the Rams will have a big dilemma on their hands.