It had been reported previously that Albion were one of numerous clubs intent on offering Aston Villa centre-back Ciaran Clark a Premier League lifeline after relegation, and that Tony Pulis saw the Ireland international as a potential key man at the heart of his defence.
However, it now appears as though the club have shifted their focus back to Caulker, whom it is claimed that Pulis tried unsuccessfully to bring to the Hawthorns last season.
Caulker endured an torrid season this term after being a mainstay for Queens Park Rangers when they were relegated to the Championship in 2014-15.
The 24-year-old spent the first half of the season on loan at Southampton, and was then a surprise January signing by Liverpool manager Jurgen Klopp on a temporary basis, but made just three league appearances for each side.
With his career having stuttered, QPR could be willing to cash in on the man who still has two years left to run on his deal at Loftus Road, and the Express & Star suggests Pulis believes Caulker would be ideal as he looks to add youth to a defence which has this season included the likes of 33-year-old Jonas Olsson and 36-year-old Gareth McAuley.
According to the paper, Pulis faces a battle with other top-flight sides to secure his primary target, and Villa's Clark could yet emerge as a more realistic signing as they continue their hunt.