After spending the second half of last season on loan at Rotherham United, Wing had impressed during pre-season - raising questions as to why the midfielder has made the switch.
Middlesbrough do now have competition for places in the attacking midfield role with Matt Crooks joining the club and Martin Payero expected to arrive soon.
“I didn’t want Wingy to go. He pleaded with me,” Warnock said.
“Hopefully Payero signs and we have Crooksy. He’s extended his contract by a year so I said to him go and play and come back here and establish yourself.
“He can easily score 10 or 15 goals in Division One, Wingy. It’s not a definite goodbye, it’s an opportunity for him.”
Boro, meanwhile, have been giving opportunities to two triallists – and one could be offered a contract before the season ends.
But they could be beaten to a key target by one of their Championship rivals.
Here’s a round-up of all the stories making the news in the second tier today.