The striker joined Aston Villa from Fulham on Thursday.
The striker joined the Villans on Thursday as they paid Championship rivals Fulham £12 million, potentially rising to £14 million, for his services.
The move came as something of a surprise, with the Birmingham club making a late move to secure him from under the noses of fellow relegated side Norwich City.
Many have questioned the fee they have paid for him, debating whether it is a smart move to pay so much for someone who turns 30 this year.
And Warnock is another one who has doubts, saying it is difficult to find a system that suits the Scotland international.
“£14 million is a lot of money,” he told talkSPORT.
“Ross is a good player and will score goals every season but it’s difficult to find a system to get success with him. It will be interesting to see how Aston Villa go.”
It remains to be seen if McCormack can justify his lofty price tag in the upcoming campaign.
He certainly knows how to score goals in the division, having managed 116 across spells with Cardiff City, Leeds United and Fulham.
Should he continue that goalscoring record at Villa Park this season, there will be few questioning the price tag come the end of the campaign.