The 18-year-old winger has impressed hugely at youth level, which has caught the eye of clubs from the Premier League and Championship.
Walker, who scored over 20 goals in pre-season alone for Rotherham's Under-18 side, has been promoted to the senior squad in recent weeks and Steve Evans handed him his debut against Cheltenham Town.
The likes of Swansea, Reading, Norwich, Blackpool and Charlton have all scouted him this season and are known to be keeping close tabs on Walker - who is yet to sign a professional deal at the New York Stadium.
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