By Wayne Veysey
Arsenal have made enquiries for defenders Winston Reid, Matija Nastasic and Ron Vlaar, Goal understands.
Arsene Wenger is attempting to push through a deadline-day deal for a new centre-back.
The Gunners' principal targets are Reid of West Ham United and Nastasic of Manchester City, with Aston Villa's Vlaar regarded by the club as an alternative if they cannot sign the other two.
Wenger wants an established defender to replace Thomas Vermaelen and provide cover for regular pair Per Mertesacker and Laurent Koscielny. His only current back-up in that position is rookie Calum Chambers.
Arsenal tried to land Greece international Kostas Manolas late in August but lost out to Roma, who bought him from Olympiakos for £10.3 million.
Nastasic, who could leave the Etihad following the arrival of Eliaquim Mangala this summer, is also wanted by Everton.
Meanwhile, Goal has learned that Arsenal's pursuit of Sporting Lisbon midfielder William Carvalho is stalling.
The Gunners made an improved bid of £21.3m for the midfield anchorman but the deal has been complicated by his third-party ownership and the Portugese club's £28m valuation.
Wenger is considering making a renewed attempt to capture long-term target Morgan Schneiderlin from Southampton.