He joined Scarborough on work experience in September 2004, and was also loaned out to Conference North club Alfreton Town in February 2005 until the end of the 2004–05 season.

He briefly spent time at Matlock Town, before joining Preston North End in December 2012 for a six-month period.

Foster returned to Lincoln City during the 2013–14 season, before spending two years as club captain at Conference Premier side Southport.

[5] On his return to Sheffield Wednesday in May 2005, Foster was released and later joined League Two club Lincoln City on a one-year contract ahead of the 2005–06 season.

[11] However, Foster did not play again for Lincoln during the 2006–07 campaign and, after training with York City, he joined the Conference National club on a one-month emergency loan on 5 October 2006 due to injuries to defenders.

[16] He made his last appearance for York in the club's 1–0 defeat to League One team Bristol City in the FA Cup first round.

[17] He subsequently mutually agreed to cancel his contract with Lincoln in January 2007, enabling him to join Conference North club Stalybridge Celtic on a free transfer.

[19] After just a month at Stalybridge, Foster returned to the highest tier in non-League football, joining Conference National club Oxford United on 16 February 2007.

[30] As a result, he missed the next two games, returning to the first-team against Ebbsfleet United on 30 August 2008, but was once again sent off, this time for a foul on Craig Stone.

[29] Foster made 44 appearances for the club during the season, scoring one goal, as Oxford narrowly missed out on a place in the Conference Premier play-offs.

[37] However, a week later, Mansfield signed Foster on a one-and-a-half-year contract for an undisclosed fee and he was instantly appointed the club captain.

[44] Foster made his Stevenage debut in the club's first Football League fixture, a 2–2 draw against Macclesfield Town, playing the whole game in the centre of defence.

[48][49] Foster played 23 times for Stevenage in his only season with the club, scoring once, and the team went on to win promotion into League One via the play-offs.

[51] Foster made his debut for the club in a 3–0 home victory against Gillingham on 27 August 2011, coming on as an 84th-minute substitute with Rotherham already holding a three-goal advantage.

[64] He made his debut on the same day in a 3–3 draw against Bury in the Football League Trophy, with Preston progressing following a penalty shoot-out.

[65] After impressing Westley in his first four matches for the club,[66][67] Foster signed a permanent contract, keeping him at Preston for the remainder of the 2012–13 season.

[69] Foster made eight appearances in all competitions during his time with the club,[65] and at the end of the season, new Preston manager Simon Grayson told him that his contract would not be renewed when it expired in June 2013.

[73] The first was scored in an FA Trophy match on 14 December 2013, netting in the 91st minute to give Lincoln the lead in an eventual 3–1 win.

[75] He played regularly throughout the campaign, making 37 appearances in a season where Lincoln struggled for consistency and finished 14th in Conference Premier.

[80] He scored his first goal for the club in his fourth appearance; his stoppage-time header gave Southport their first win of the season in a 2–1 victory over Altrincham at Haig Avenue on 23 August 2014.

[84] However, Foster started to struggle with the commute to Southport from his home in Barnsley each day[79] and subsequently joined local National League North club Harrogate Town on 24 February 2016, on a contract until the remainder of the season.

[79] He featured frequently during the opening months of the season, but suffered an injury in an FA Trophy defeat to Barwell in October 2016.

[87][88] He spent five months at Coalville, leaving the club in April 2017 after being appointed as Oldham Athletic's new commercial manager on 28 March 2017.

[92] He made his debut for Goole in a 2–1 loss at Trafford on 16 September 2017,[93] and went on to make five appearances in all competitions during a one-month spell for the club.

[94][95] Having initially been linked with a move to Loughborough Dynamo in February 2018,[96] Foster eventually signed for the Northern Premier League Division One East club on 14 July 2018.

[102] This was his only appearance for England C.[103] Foster has described himself as a "family man",[2] but admits to making bad lifestyle choices in his "younger years".