Two years ago, Campbell signed a 5 year contract for $5M a year with the expectation he could be a Stanley Cup winning goalie. Instead he completely melted down, and in November of this year, the Oilers sent him down to the AHL for the whole season. It was clear the trust is broken, and honestly, Campbell looked like he would struggle to become an NHL goalie again.
Today was the final day teams are able to complete a buy-out process before free agency, and the Edmonton Oilers needed the cap space. The Oilers were trying their best to trade Campbell up until yesterday, but they had been trying to trade him for a full year. Simply put, no one was taking his contract without being paid handsomely.