New transfer rumors before the January transfer window re-opens suggest that Manchester United will be strictly dealing with its weak defense tactics, of late, and will make the first move by trying and signing Serbian defender Neven Subotic, who has been closely monitored by the Red Devils from German club, Borussia Dortmund.

Subotic, according to reports, is United’s primary defensive target this season as United boss Sir Alex Ferguson wants an extra defender apart from the likes of Serbian Nemanja Vidic and Jonny Evans of Northern Ireland. It is also believed that Sir Alex made such a move owing to the current poor form of his most experienced campaigner Rio Ferdinand, who himself is linked with a move to Tottenham.

Subotic is one of the most wanted players in Europe and has been monitored by top European clubs. His current club, Borussia Dortmund, however, has managed to ward off any real threat to lure away the priced defender from the club including turning down Chelsea’s £17.5 million bid.

It has also currently been reported that the German club may have to sell a player to balance the books. This may happen if the club fails to get the financial boost of continued progress to the knock-out stages of the Champions League.

United, thus far in the season, have conceded 12 goals in 10 games, and four in three Champions League matches and the Red Devils' boss has been forced to try out different centre back partnerships to retain normalcy in the back. Although players like Nemanja Vidic, Jonny Evans, Chris Smalling and Phil Jones have shown enough quality in the defensive area, there is still concern about Rio Ferdinand’s form.

Dortmund, for that matter, has also collected just one point from three group stage matches in Europe, according to a Caughtoffside report.

Subotic made his professional debut for Mainz 05 in the last match of the 2006–07 season against Bayern Munich as his team was relegated from the Bundesliga. He was signed by Dortmund on a five-year contract in 2008.

He debuted for his new club in the unofficial German Supercup match against Bayern Munich, which Dortmund won 2–1. In the 2009–2010 Bundesliga season, Subotic was one of only four players in the entire league to play every minute of every league match.

Subotic got his first goal ever in the European competition in 2010 at Sevilla in the Europa League to tie the score at 2–2.