The month of January is the only part of the season during which professional soccer clubs are allowed to sign new players from other teams. This season, Arsenal have been in the market for a desperately needed tall striker to replace the injured Robin Van Persie. So far, however, Arsenal have not signed anyone. But reports today (for example, here) confirm that Arsene Wenger is about to sign a former Arsenal central defender, the 35-year-old Sol Campbell (pictured right). This cuts strongly against Wenger's usual practice of not resigning former players, not to mention his strong preference for younger, quicker players.
I can only assume this means that current back-up Philippe Senderos is out of favor and will shortly be sold. Certainly, Arsenal don't need Campbell in their regular starting line-up, where William Gallas and Thomas Vermaelen have formed a strong partnership. However, Wenger may plan to use Campbell in some kind of rotation with the other two. He has predicted that Campbell could yet make the English World Cup team, but that couldn't possibly happen if Campbell mostly sat on the bench at Arsenal.