The former Aston Villa frontman took to social media over the weekend to offer praise to Leeds winger Crysencio Summerville.
Posting on Instagram, McCormack said: “Fed up telling yous. Best player in the league.”
Summerville has established himself as a key figure under Whites boss Daniel Farke this season, scoring four goals across nine Championship outings.
Two of those goals came at the weekend, when his brace completed a dramatic comeback victory over Norwich City.
The win lifted Leeds into third place in the Championship, six points behind Ipswich Town in second.