He broke his ankle and fibula, and suffered ligament damage competing for a ball on the touchline after his foot stuck in the ground.
After his injury, Butler could not recapture the form for Reading that he'd shown before, and after floating in and out of the first-team, he was sold to Rotherham United in a £150,000 deal in August 2003.
In an attempt to amend relations with Grimsby, Butler returned to regular training and won back his place in the side next to Danny North and helped the Mariners climb from 19th in League Two, to 10th.
Despite Butler's renewed attempts to salvage his Grimsby career, he reignited his travel problems, and this eventually saw the player drop out of contention at the club.
He played his last game for the club in the League Cup fixture with Blackburn Rovers and after that he was shelved by Buckley who dropped him to the reserves, which is where he remained for the rest of his time at Grimsby before he was eventually released in October 2008 by the club's new manager Mike Newell due to the aforementioned travel problems.