Nottingham Forest still expect to make three more signings despite the transfer window being closed, according to owner and chairman Fawaz Al Hasawi.
Al Hasawi said on Twitter a quartet of players had agreed to join and the paperwork had been submitted in time.
His tweet came before the club said it had signed Brighton's Chris O'Grady.
Crystal Palace's Wales midfielder Jonny Williams is set to sign, while Lille winger Ryan Mendes and Benfica striker Nelson Oliveira have also been linked.
"I can confirm four players have agreed to join," Al Hasawi said. "All paperwork was submitted before the 6pm (18:00 BST) deadline."
Hasawi added any deals will be announced via the club's website and Twitter account.
Hasawi said the money from the Antonio deal, thought to be around £7m, would enable the club to exit their transfer embargo at the end of the season.
For confirmed transfer deadline day deals, click here.