The 22-year-old striker has made four Scottish Premier League appearances for Celtic this season.
“I have signed a new contract for two years on Wednesday there, so I was delighted to get that sorted,” explained McGowan.
“I worked with Neil before and got on with him well. Obviously, Tony Mowbray was starting to take a liking to me and then the sacking came, but that’s football.
“I was in a no-win situation. I am not 23 yet. If I knock the offer back, somebody has got to come in and pay X amount of compensation and there’s no money going about in the game.
“But that is not a problem. I was delighted to sign and I am confident in myself whatever manager comes in.”
