The Wales veteran was on the bench for victory at Fulham.
"The change at Fulham was just to have a little bit of fresh impetus," said Mackay to the Western Mail.
"Craig is a massive part of everything we are doing here. He's one of my main men. He's one of the main leaders in the dressing room.
"But it's about the squad. It's about making sure we've got the right players out there and that we are making the right changes at the right time.
"That's something I've done here for the last two years. People come in based on form and just the feeling they can do something that week.
"Bringing Odemwingie in was right. He looked very dangerous in that position for us."
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