season against Birmingham City. He scored his first goal in Blades colours at the end of August, away at Huddersfield Town in the second round of the League Cup. Although a regular starter he missed a number of matches through injury and suspension, scoring only 6 more goals in the 2008–09 season. The following season, he was again favoured as the Blades main striker and netted twelve times before once again being hit with an injury that would eventually keep him out for almost twelve months. Henderson returned to the Blades first team in March 2011 but was red carded during his first game back, and made only eight appearances that season, scoring two goals, as the Blades slipped to relegation. Millwall With the Blades struggling to maintain their wage bill following their relegation to League One they agreed to sell Henderson to Championship side Millwall at the end of June 2011 for an undisclosed fee. On 22 October 2011, Henderson scored a hat-trick against Leicester City. The game ended 3–0 to Millwall and earned the team valuable points to steer them out of the relegation zone. Henderson scored his second and third hat-tricks for Millwall within a week, in a 5–0 FA Cup win over Dagenham & Redbridge and a 3–1 away win at Barnsley. He followed this up, scoring the equalizer against Southampton in an FA Cup fourth round tie. This goal took his tally for his season to 16, from 22 matches. It was also his 100th professional goal. During the close-season, Henderson was reportedly being chased by several Championship rivals but Kenny Jackett was keen to keep him. Nottingham Forest Henderson joined Nottingham Forest in January 2013, agreeing a short-term deal to run until the end of the season, after Millwall agreed to allow him to leave on a free transfer to help cut their wage bill. In June 2013, Henderson agreed a further two-year deal with Forest, with an option of a third year. Leyton Orient On 1 August 2014, it was announced that Henderson had signed a three-year contract with Leyton Orient. Scunthorpe United On 24 July 2015, Henderson joined Scunthorpe United upon his expiry from Leyton Orient. Coventry City On 5 February 2016, Tony Mowbray confirmed Henderson had signed for Coventry City.. Mansfield Town Henderson joined Mansfield Town in August 2016. He scored his first goal for Mansfield in a 3–1 win against