Cooper, who missed opportunities for Leeds in their 1-0 defeat at Wolves on Friday night, has come in for criticism, with some questioning whether he is of the standard needed for the top flight.
Whelan thinks that Cooper must be cut some slack because he has had to operate with different centre-back partners and also suffered with injury himself.
The former Leeds man is pleased with how Cooper has performed so far this term for Marcelo Bielsa’s men.
“Look, I’ve been fairly happy with him.”, Whelan said on BBC Radio Leeds after the result at Molineux.
“At the end of the day he’s not had any real centre-half partner for very long.
“He had an injury himself and I do believe he’s been the most aggressive out of the centre-halves that we’ve had.
“I think it is probably that he had a lot of chances [against Wolves] that he missed that he is probably getting a lot of flak as well.”
Leeds have struggled defensively in the Premier League this season, shipping 43 goals in their 24 games, the second worst defensive record in the division.
Cooper has turned out in 18 of Leeds’ top flight matches, getting on the scoresheet once, in a 6-2 loss at Manchester United.