Hearts released a statement on Friday revealing the player would move on after the deadline the club had given him to agree to a new deal had passed.
Devlin, it is reported, is now set to join Rangers.
Vrancken had a positive phone call with the Aussie earlier this week, but expressed his disappointment that he won’t get to work with the player.
“As a coach, of course, we want good players to stay. It’s disappointing because I had a good phone call with him and sent some text messages with him. It’s always disappointing to see a player go who has personality and quality,” he said following Hearts’ 2-1 friendly loss to Livingston.
“But you cannot keep waiting for him to decide. When he really wants to stay, he could decide earlier or today. When he keeps postponing or delaying it…
“I think he was honest with me. The feeling I had, I just know him from the phone call, but he seemed like a really good personality, a good guy.
“I think he was honest in that he was in doubt at that moment for what he wanted. There were already a few days in the World Cup after we called and then he had time enough to make a decision.
“As a club, you have to move on.”
Vrancken confirmed that Hearts will look to see what they can do in the transfer window with the hope of adding to the different profiles in the squad.
“I always focus on the players I have at the moment. I knew he was end of contract, so you work with the guys who are there,” he said.
“I had a good chat with him, and it’s a pity. I think we now have some profiles and types we don’t have in the squad at the moment, so we now have to see what we can do.
“I think when Cammy is not coming, we need something there for sure. I think we can have some type of profiles we don’t have in the squad at the moment. But, yeah, that we have to see with recruitment.
“But, yeah, it’s a pity that he’s not staying.”