The 11-goal top scorer was only introduced as a 74th-minute substitute after being left out in favour of Paul Benson as Pompey fell to a 2-1 defeat. It was the first time this season that McLeod has been dropped, but Whittingham was quick to dispel any conspiracy theories about the 28-year-old's future.
"Izale has done a fantastic job for us when he has played in that wide area," he told the Chichester Observer.
"We just thought that Paul Benson was the right way to go and felt Mendez-Laing might create something for us.
"Benson is a bit more combative in the air, he is better coming to the ball. Whereas, it is no secret Izale is one of those who you want to put in a ball for him to run on to."
McLeod's contract expires on January 16 and Whittingham expects a battle to keep hold of him.
"Izale has not said anything at all that he could be going," he added. "Of course I am expecting interest, though. He's our top scorer with 11 goals this season and up among the highest in the league.
"I would be interested in him if I was somewhere else. Especially as he's a free agent. All players want is a bit of security and at the moment this football club cannot offer it.
"It can offer great fans, great support, what I think is a good coaching side of things with top staff. What we cannot offer them - if they are looking for it - is security and for that reason some could go next month."