for Stevenage just came out of the blue. With all the trouble Salisbury were in we did not know what league we were going to be in next season and as such the club couldn't offer contracts". Sinclair made his Stevenage debut in the club's first ever Football League fixture, a 2–2 draw against Macclesfield Town on 7 August 2010, coming on as a substitute in the 71st-minute of the match. He subsequently started in the club's next game just two days later, playing 75 minutes in the side's 2–1 defeat to Portsmouth in the League Cup. Sinclair scored his first goals for the club on 26 March 2011, scoring twice in Stevenage's 4–0 victory against Macclesfield Town at Moss Rose. Sinclair suffered a groin injury in training the week after Stevenage's 3–3 draw with Bury, resulting in him missing Stevenage's successful play-off campaign, which resulted in the club earning promotion to League One. He played 31 games for Stevenage in his first season with the club, scoring two goals. The injury ultimately ruled Sinclair out of the first half of the 2011–12 season. Sinclair revealed that there had been a number of complications with the injury, with his "tendon coming away from the bone by two centimetres", as well as the doctor refusing to give him injections as a result of the tendon movement. Having failed to make any first-team appearances for Stevenage as a result of the injury, Sinclair joined League Two club Aldershot Town on a one-month loan deal on 13 March 2012, in order to gain match fitness. He made his debut for Aldershot later that day, coming on as an 85th-minute substitute in a 2–2 away draw with Crawley Town. Sinclair made four appearances during his loan spell at Aldershot, three of which as a substitute. He returned to Stevenage on 9 April 2012, but ultimately did not make any appearances for the club during the campaign. In June 2012, Sinclair left Stevenage despite being offered a one-year contract extension, stating he wanted to play first-team football and did not want to be "a bit-part player". Three months later, in early September, he rejoined the club on a one-year contract. Having not played for Stevenage during the opening months of the 2012–13 season, Sinclair joined Aldershot Town for a second loan spell on 6 November 2012, joining on a one-month agreement, which was later extended