The club has signed former Swansea City and Aston Villa defender Neil Taylor on a short-term contract.
The 32-year-old left-back, who won over 40 caps for Wales, has officially joined the club after arriving at Rockliffe to join training last week.
Taylor, who left Aston Villa at the end of last season after clocking up over a century of appearances for the club, had a run-out in our Under-23s win against Nottingham Forest last Friday.
Neil has a wealth of experience, he spent six seasons with Swansea in the Premier League before becoming a promotion winner with Villa.
Boro boss Chris Wilder said: "Looking at the market we're in at this particular time it's a great one for us.
"He adds balance and competition to Marc Bola which is desperately needed.
"Neil's a player of pedigree with a great attitude. He's still fit and played for the U23s for an hour last week, I think it's a smart bit of business until the middle of January then we can go from there."