Real Madrid have announced an agreement to sign highly-rated teenage defender Jesus Vallejo from Real Zaragoza.
Aston Villa have continued their spending spree after securing the services of Rudy Gestede from Blackburn on a five-year contract.
The 19-year-is currently recovering from a thigh injury, which he picked up whilst on loan at League One promotion chasers Tranmere Rovers - where he has impressed hugely.
Gibson - who made his Boro debut back in 2011 - has gained substantial firs-team experience in the past 18-months having also spent time on loan at Plymouth and York before linking up with Tranmere.
Gibson - nephew of Boro chairman Steve - is now recovering at Boro, who have rewarded his progress.
"He's playing in a position that's pretty crucial and I've told Ben that," said Boro boss Tony Mowbray.
"It's pretty difficult to throw a 19-year-old into a team that's trying to get us out of this division.
"With a tricky wide player it's a lot easier to get them into the side but it's particularly difficult to do that in central defence.
"At this level they'll be playing against experienced, hardened pros up front. At centre-half, one slip and the ball is in the back of the net and so experience and knowledge is important."
Mowbray is pleased with how Gibson has performed during his loan spells, especially his time with Tranmere.
"It augurs well for Ben. He's done extremely well at Tranmere and who's to say they won't be in this league next year?" he said.
"In the group we have Andre Bikey, Jonathan Woodgate and Seb Hines, who are all more experienced.
"But at some time in the next year or two Ben Gibson is going to be knocking on the door of the first team.
"He's a very, very mature young guy who's very focused and knows what he wants from his career."