Sunderland boss Steve Bruce has predicted it will be only a matter of time before a player challenges the transfer window system as a restriction of trade.
The Black Cats faced an anxious wait to see if they had landed Manchester City striker Benjani Mwaruwari on loan earlier this week after communications problems left the Football Association and the Barclays Premier League to make a decision on whether or not the deal had gone through in a mad rush before Monday's 5pm deadline.
"I wouldn't be surprised if a player stops it by saying it's a restriction of trade, said Bruce.
"Take Benjani for example. Benjani has come up here now to try to earn himself a contract. If the deal hadn't gone through, then it restricts his career, it restricts his movement.
"That's why we carry the squads we carry. They are too big and we can't keep them all happy."
Bruce, however, was delighted to have landed Benjani at the end of a transfer window which saw him frustrated in moves for the likes of Kevin Kuranyi, Maynor Figueroa and Habib Beye.
He moved for the City frontman after deciding to allow David Healy and Daryl Murphy to join former boss Roy Keane on loan at Ipswich.
Bruce said: "In the back of my mind, I knew there was a deal for Murphy and Healy and with the injuries we have had, I was juggling thinking, 'Do I let Murphy and Healy go?' because the one thing they want to do is go and play football and they weren't going to play here.
"I thought to myself, 'If I am going to do that, I have got to bring somebody in'.
"I wanted somebody with a bit of know-how and a bit of presence, and somebody who as been there, done it and worn the t-shirt in the Premier League, and I am delighted we got Benjani in the end."