Youngster Trai Hume became Sunderland' s first January signing, with the Black Cats paying a six-figure sum to sign the talented right back from Linfield.
And now, Danny Batth has opted to join the Black Cats on an 18-month deal, becoming the second signing of the January transfer window after Hume and Sunderland have not paid a fee for the defender.
Johnson says that he has twice signed to sign Batth in the past, who has twice promotion from League One.
The Sunderland head coach has cited his leadership qualities as potentially crucial for the second half of the season.
But who else have Sunderland been linked with?
Here, we take a look:
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5. Freddie Ladapo
Sunderland are said to be interested in Rotherham striker Freddie Ladapo after he recently handed in a transfer request. Photo: George Wood
6. Dan Jebbison
Recent reports stated that the Black Cats are still trying to do a deal to bring Dan Jebbison to the Stadium of Light after he joined Burton on loan in the summer. Photo: James Williamson - AMA
7. MIDDLESBROUGH, ENGLAND - JANUARY 27: Boro player Patrick Roberts in action during the Sky Bet Championship match between Middlesbrough and Rotherham United at Riverside Stadium on January 27, 2021 in Middlesbrough, England. Sporting stadiums around the UK remain under strict restrictions due to the Coronavirus Pandemic as Government social distancing laws prohibit fans inside venues resulting in games being played behind closed doors. (Photo by Stu Forster/Getty Images)
Sunderland were said to be confident of signing Manchester City’s Patrick Roberts but the noise surrounding the deal has gone quiet. Photo: Stu Forster
8. Patrick Kelly
Promising Coleraine teenager Patrick Kelly, 17, is the latest striker to be linked with a move to the Stadium of Light with Kristjaan Speakman targeting youth. Photo: FRANK REID 2020