Grimsby move for Ramsden
The 23-year-old has put pen-to-paper on a one-year contract with The Mariners following his release from The Black Cats last month.
The deal includes a one-year option following the completion of his initial 12-month deal.
He joins former Hull City captain Justin Whittle in making the move to Blundell Park after completing his medical with the Coca-Cola League Two club last week.
Ramsden was pleased to be making the move to Grimsby for the upcoming campaign.
"I'm signing for a year with a year's view and I'm delighted about it to be honest," Ramsden told the club's official website.
"My contract was up with Sunderland and Grimsby had shown a lot of interest.
"I came down and I was really impressed with what I saw - I signed without hesitation."
Slade, meanwhile, also signed young goalkeeper Paul Fraser to his first professional deal with his hometown club last week.