The 29-year old Dutch defender made just 10 appearances for the Hoops during his 18-month stay at Parkhead with injuries cutting his time short.
Hooiveld went on loan to Southampton last year and helped the club gain promotion to the Premier League, earning himself a permanent deal to join the Saints but he still feels irritated at not being able to give everything he could to the Celtic cause.
“I only played ten games – and they were not always the best results.
“If you look back, I got my chances in the team when I wasn’t at my strongest, fittest or most confident.
“I think you could see that on the pitch. It was just unfortunate that things happened that way.
“Sometimes things fall for you, sometimes they don’t. It never really happened for me at Celtic.
“I’m only focused on Southampton. Everyone will have an opinion, but you can’t change that so it’s not my motivation.”