Sunderland ended the January transfer window on a high as they secured a deal to bring Jermain Defoe back to the club on a free transfer.

The Black Cats were busy throughout the month as they brought in a number of players to bolster the squad in their attempts to secure promotion back to the Championship

Trai Hume, Patrick Roberts, Danny Batth, Jack Clarke and Jay Matete all came through the door permanently or on loan over the course of the window alongside the former England international.

Forget Defoe

Whilst it was great to see the ex-Rangers man back at the Stadium of Light, Kristjaan Speakman did endure a deadline day howler as he sanctioned an exit for centre-back Tom Flanagan and failed to bring in a replacement.

Terence Konogolo was reportedly a player of interest to the club but they were unable to get a deal over the line for the former Fulham defender. This meant that they allowed Flanagan to leave and left themselves short on options at centre-back heading into the second half of the campaign.

The Northern Ireland international played a major role in Sunderland's success in League One heading into deadline day. He started 25 of their 29 matches and averaged an impressive SofaScore rating of 7.10, showing that he was able to regularly deliver quality performances at the back in the third tier.

Flanagan made an outstanding 5.1 clearances, 1.5 tackles and 1.6 interceptions per game. The centre-back was a defensive wall for the club at times and his statistics back this up, as he was able to consistently win the ball back for his side whilst also defending his own box with key clearances.

This shows the level of quality Sunderland have lost by selling him to Shrewsbury on deadline day, with no direct replacement coming in. The £3.6k-per-week "leader" was able to perform to a high-level week-in-week-out for the Black Cats and it is impossible to guarantee that anyone will be able to replicate that.

Batth came in earlier in the window and is yet to convince that he is the long-term answer to any of the club's issues at centre-back. In his second appearance for the club, he scored an own goal and recorded a dismal SofaScore rating of 5.9 in a 6-0 defeat to Bolton, which comes as a worrying sign given that he could now be expected to step up and fill Flanagan's spot in the team.

Therefore, Speakman endured a deadline day howler with his decision on the centre-back and it could be a call that he lives to regret at the end of the season if Batth does not hit a run of form to help the team secure an automatic promotion place.