The 28-year-old Wales international's contract is due to expire this month and he has now confirmed that he will not be staying with the club.
The central midfielder has been linked with the likes of Sunderland and West Brom, as well as Scottish champions Rangers.
"It was a very good offer and it was a tough decision, but I just want to stay in the Premier League and test myself at the highest level," he told the club's website.
"It was unfortunate that we couldn't quite stay up last season and that was a big disappointment.
"My three years at Blackpool have been great and I'd really like to thank the fans and the staff. The last couple of years have been brilliant and I leave with nothing but good memories.
"If it wasn't for Blackpool I may never have played in the Premier League, so I have a lot to thank the club and the manager for. He has changed things around and I'll always look back on my time with fond memories.
"It's a tough decision to move because my family are settled in the area, but hopefully things will work out well wherever we end up."