The Ibrox chief is said to be in firm contention for the Rams job.
The Rangers boss could be difficult to prise away, having led the Light Blues back to the top flight, but may be tempted by a return to the division where he tasted (albeit fleeting) success with Brentford.
Neither Scott Carson or Lee Grant have convinced in goal, meaning a new number 1 could be sought by Derby this summer. Foderingham, meanwhile, has impressed in his first season at Ibrox and the Londoner may fancy a return south, especially if rumours linking the Light Blues with Southend shot-stopper Daniel Bentley prove to be true.
Derby have been without regular left-back Craig Forsyth for much of the campaign due to a cruciate ligament injury which could eat into the summer, and while Marcus Olsson arrived from Blackburn in January Stephen Warnock has been released, potentially leaving the Rams in need of reinforcements. Wallace, though, has stuck with Rangers throughout their recent ride, and may be difficult to lure away - but Warburton's influence could change that.
Derby's wide men have flattered deceive on the whole this season and McKay, who scored nine goals and made another 13 this season, would freshen things up in that department. The 21-year-old - a right footer who can operate on either side and centrally - recently received full international recognition for his displays. His arrival may hinge on whether the Rams can offload any of their current crop, including January additions Abdoul Camara and Nick Blackman.