[3] Thomas played as a defender and has represented twelve clubs, including Torquay United, Stoke City, Burnley and Southampton.

His performances soon brought attention from larger clubs, with Stoke City, then in the Second Division, winning the race for his signature in the summer of 2001, paying a transfer fee of £200,000.

[5] In the 2001–02 season Thomas helped Stoke achieve promotion through the play-offs with a 2–0 win against Brentford at the Millennium Stadium in the final.

He had a difficult start to the season, being deemed at least partially at fault for some goals conceded and being sent off twice before the end of September, however Cotterill showed faith in him by retaining him as captain on his return from suspension.

[16] Thomas joined up with his old club Stoke City for pre-season training,[17] before signing for Doncaster Rovers on 10 August on an initial one-year contract.

Thomas returned to England in January 2013 and on 4 February he joined Conference Premier side Luton Town until the end of the 2012–13 season.

[29] Alongside his role at Tamworth, Thomas was the under-11s academy coach at Premier League club Stoke City.

[31] On 18 October 2014, in a match against Harrogate Town, Worcester were without a recognised goalkeeper after Jose Veiga suffered an injury, so Thomas played in goal and kept a clean sheet in a 2–0 win.

[36] In October 2017, Thomas returned to Worcester City as a player; on his second début for the club, he was sent off for raising his arms to an opponent.

[37] In March 2018, Thomas left Worcester City to take a job at a West Bromwich Albion soccer school in China.