Towards the end of the 2004/05 season Robson established himself as a regular in the team at left back, though he lost his place the following season as Martin Scott preferred Ritchie Humphreys. Robson`s appearances after that were usually in a more advanced role on the left of midfield, and the position seemed to suit him better. He looked to be establishing himself in the side in the first half of the 2006/07 season, but his chances were dented in the middle of that season when Danny Wilson brought Andy Monkhouse to the club from Swindon Town. Monkhouse brought a greater consistency and goal threat to the left win and from his arrival Robson was relegated once again to a supporting role.
A short run of effective substitute appearances around Christmas 2008 saw Robson briefly displace Monkhouse from the first team, but he lost that place through a minor injury in the new year and never regained it. He turned down the offer of a new contract in the summer of 2009, and later joined Carlisle United.