 He subsequently entered talks with Cambridge United in January 2010, although nothing materialised. Mansfield Town also enquired about signing Foster, although they initially decided against making a bid, citing Foster's "high wages as the main stumbling block". 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. He made his debut in Mansfield's 4 – 1 victory over Forest Green Rovers, but was sent off in a 1 – 0 defeat to York in March, which resulted in him receiving a two-match suspension. He made 16 appearances for Mansfield during the second half of the 2009 – 10 season. At the end of the season Foster made a comment on his Facebook page, calling the club a "shambles", but later apologised to both the club and its fans. He was released in May 2010, with Mansfield boss David Holdsworth saying "it's a practical decision for both the club and Luke".
