Chelsea are the latest club to be linked with a move for Birmingham defender Scott Dann.
Stoke City were the first Barclays Premier League side to make their move, with manager Tony Pulis confirming the Potters were waiting to hear back over their bid over the weekend.
Arsenal boss Arsene Wenger has also been tracking the player, according to reports, with the Frenchman interested in bringing the player to the Emirates in an effort to strengthen in the position.
Defensive injuries hit Arsenal hard last term, with Thomas Vermaelen the major absentee throughout. The Belgian international was missing for the majority of the season with an Achilles problem, and it proved to be an area of constant concern for the Gunners.
Dann is one of a handful of players in the centre back position linked with a move to north London, with Gary Cahill and Christopher Samba also thought to be of interest to the Arsenal boss.
Competition for Dann will be fierce though, with the Daily Mirror now reporting that Chelsea boss Andre Villas-Boas has taken an interest in the former England U21 international.
The former Porto boss said at the end of last week that he was keen to bring a British defender to Stamford Bridge in the summer window, with Dann now emerging as a front-runner for the move.
Reports in the same paper say the Chelsea boss is also studying footage of Cahil and Jack Rodwell, and will be looking to recruit one of the players before the start of the season.
The claims come just days after rising star Jeffrey Bruma left Chelsea for Hamburg on loan, whilst Jose Bosingwa and David Luiz have also been linked with a move away from west London.
Birmingham have so far held firm over Dann, but the club's relegation to the Championship now makes a move likely, and competition has heated up further with Chelsea now joining Arsenal and Stoke in the already intense chase of the 24-year-old.