The Bucks boss revealed he is still waiting on decisions on the futures of some members of last season’s squad.
And Cowan declared he ‘will not wait forever’, adding that he has looked into alternatives should those he was keen to keep on board opt to look elsewhere.
Theo Streete, Ellis Deeney and Marcus Dinanga are three regulars from Cowan’s ranks last season whose futures are yet to be clarified.
The boss said: “We’re still in talks with a couple of them and are waiting to hear back. I’ve told them all, I’m not waiting forever.
“I suppose my mind is made up and the time has gone now. Those players run the risk of me recruiting other people. The timescale has moved on now and I’m looking for alternative players.
“I was very, very on the front foot and proactive about who I wanted to keep and who I didn’t.
“If they want to drag that out it’s totally up to them. I’m in a position now where I’m recruiting for the positions I need.
“If those players come back before I recruit someone else then so be it and if not then they miss out.”
Cowan has so far agreed new deals with Brendon Daniels, Adam Walker and Zak Lilly.
Shane Sutton, Ross White and Aaron Williams were already contracted for the 2020/21 season.
Telford have been awarded a £1,500 Pitch Preparation Fund grant from the Premier League, FA and Football Foundation to help cover pitch costs.
Henry Cowans has been invited to pre-season training, while James McQuilkin, Darryl Knights, Jon Royle and Arlen Birch have been released.