first team place at the start of the 2004–05 season and by September 2004, was seeking a move away from the club. A transfer did not materialise and with his first team chances limited, he made only 20 appearances for Sunderland in the 2004–05 season. At the end of the season, he was transfer listed. Doncaster Rovers Following Sunderland's promotion to the Premier League in May 2005, Thornton was sold to Football League One club Doncaster Rovers in July 2005 for a club record fee of £175,000. He made 36 appearances for Doncaster in the 2005–06 season, missing several weeks owing to an ankle injury suffered in September 2005 that needed surgery. He helped Doncaster reach the quarterfinals of the Football League Cup, putting in a fine performance and scoring the third goal when Doncaster beat Premier League club, Aston Villa 3–0 in November 2005. Manager Dave Penney praised Thornton, saying: "It was a great goal for Sean and he's looking much brighter and sharper these days, and long may that continue." After the game, Thornton said that he felt had made the right move in the summer, saying "It was a gamble for me. I still had two years left on my contract at Sunderland. It was one of them – would I go, would I not go? Obviously we're playing good football and I think I made the right decision. Now, hopefully, we can carry on the success until the end of the season and get promoted. That's the main thing." In the 2006–07 season, Thornton made 41 appearances, and helped Doncaster to victory over Bristol Rovers in the Football League Trophy final in April 2007 when he swung in a corner kick for Graeme Lee to head in to score the extra time winner at the Millennium Stadium, Cardiff. Leyton Orient Thornton was released by Doncaster manager, Sean O'Driscoll at the end of the 2006–07 season, and joined another League One side, Leyton Orient in July 2007 on a two-year contract. Orient manager Martin Ling said that he was "... pleased to have Sean on board. We've been looking for a creative midfielder and Sean fits the bill perfectly. He will fit into our style of play and I believe we have signed a quality player." He scored on his debut against Southend United in August 2007, with a spectacular free kick from 30 yards in a