The Norwegian defender made the move to St Mary's in January but was unable to break into the Saints side and did not make a single appearance before the end of the season.
Molde have expressed an interest in taking the 25-year-old back for a temporary spell, but he has ruled out a move.
"I am very fond of Molde and hope they do well," he said in the Southern Daily Echo. "But right now it's not an option for me."
Molde boss Ole Gunnar Solskjaer also confirmed that he had contacted Forren to enquire about his availability.
The former Manchester United striker said: "I've talked to him about if it could be appropriate but it was not."
The Norwegian season had already finished when Forren joined Southampton in the winter and his agent, Jim Solbakken, has previously indicated that he was signed with a view to the 2013/14 campaign.
"When we took Vegard to Southampton it was obviously in the middle of the season (in England) and he came from holiday, so it was agreed he was going to build his fitness towards this summer's pre-season and upcoming season," Solbakken explained.
"It is obviously a huge step for a player coming from Norway to the Premier League and it takes time.
"He is patient, ready and committed to that. We knew what was coming and we all agreed."