[5] Barnett made his debut for Tranmere Rovers away to Swindon Town, in the 3–1 defeat in League One on 9 August 2008.
[6] However, he spent two months on the substitute bench, due to manager Ronnie Moore's decision to "inject greater defensive discipline into the midfield".
[8] It wasn't until on 24 October 2008 when Barnett made his first team appearances for the first time in two months, coming on as a late substitute, in a 2–0 win over Crewe Alexandra.
On 17 July 2009, he signed a new one-year contract at Tranmere Rovers, ending speculation over a potential transfer move.
[16] His first appearance of the season came on 25 August 2009, coming on as a substitute in the 65th minutes, in a 1–0 loss against Bolton Wanderers in the second round of the League Cup.
[17] However, he received a straight red card for "a lunge on Neil Austin", in a 1–0 loss against Hartlepool United on 24 October 2009.
[24] Barnett made his Accrington Stanley debut on 7 August 2010 in the opening match of the season against Aldershot Town.
[35] After serving a three match ban, Barnett returned from suspension, coming on as late substitute, in a 1–1 draw against Oxford United on 24 September 2011.
[37] Seven days later on 8 October 2011, Barnett helped the side by setting up two goals to come from 2-0 down with 10 men to claim a point, in a 2–2 draw against Plymouth Argyle.
[44] He later sent–off in the 4th minutes of the first half for a professional foul on Daniel Jones, in a 3–0 loss against Port Vale on 4 February 2013.
[48] Barnett made his AFC Telford United debut, where he started a match before being substituted in the 67th minutes, in a 2–1 win over Workington in the opening game of the season.
[50] He scored his first goal for the club at home to Hednesford Town in a game which Telford won 5–3 to take them top of the Conference North on 1 January 2014.
[54] Ahead of the 2014–15 season, Barnett was expected to make an impact for the side by the club's manager Liam Watson.