Allan Campbell will leave Motherwell this summer after manager Graham Alexander failed with one last attempt to keep the midfielder.
The 22-year-old rejected an improved contract offer and will leave when his contract expires.
Motherwell will be entitled to compensation following Campbell's 13-year stay at Fir Park, during which he has made more than 150 first-team appearances and won 24 Scotland Under-21 caps.
Alexander said: "I had one last shot at it a couple of weeks ago and we did offer him a very good contract, for us, because I didn't want to get to summer and he goes elsewhere and we hadn't tried everything we can to keep him. Because he's a brilliant player, a brilliant professional, and any manager would be desperate to keep him on board.
"I understand the reasons why as an ex-player myself. We had a great chat and he was honest, as he always is, and I could see his perspective.
"He will be leaving in the summer and I hope he gets the best club he can because everyone at Motherwell would wish the best for Allan because he has been absolutely fantastic for this club.
"I think he can go all the way. Not right now, he is still young, he has still got little bits to improve in his game. But if I know anything about Allan Campbell, he is going to do everything he can to improve.
"But already he is a quality player. As you go through the levels, you have to find that little bit extra. Allan Campbell will search for that little bit extra and get it.
"Nothing would surprise me in what Allan Campbell goes on to achieve in the next 10-15 years."
The news comes days after Aberdeen announced a pre-contract deal for Motherwell skipper Declan Gallagher.
"Going from my conversations with Dec in January, we did speak about the possibility of him signing a pre-contract elsewhere," Alexander said.
"All I said to him was, if it does get done at some point, if I don't see any deviation in his training and way of behaving and playing, then nothing changes for me.
"It's not ideal that it's out publicly, but that's not our doing.
"I haven't spoken to Dec since the announcement, I haven't asked him about it. I go on what I see from people rather than what I hear from people. All I want to do is see as many players motivated to win the next two games as possible."
Alexander will resume contract talks with striker Devante Cole after Sunday's final Scottish Premiership game and he will continue to pick his strongest team for Wednesday's clash with Dundee United at Tannadice.
"My motivation every week is to win the next game," he said. "Next season doesn't really come into account, it's about this season.
"Players will always have to look to their future and protect their future, as do clubs. We have been looking to recruit for a few months now. So for me to sit here and expect a player not to sort his future out would be a bit naive and a little bit selfish.
"So I've got no problems with players sorting their futures out as long as they do what's expected of them by who they are paid by."