Cork spent 14 years at the Bridge before joining Saints at the start of last season but never played a first-team game.
Cork said: “Chelsea was massive for me and from the age of eight it was my dream to play for them. It was frustrating towards the end but I loved it when I was there.
“We had a good set of young players who have all gone on to play a high standard. That was when Chelsea were doing well and winning titles — so I can understand why nobody was given a chance.
“With the managers chopping and changing there is always a lot of pressure on them to win games, so it’s tough to blood youngsters.”