 However, Stevenage failed to achieve promotion to League Two following an aggregate 4–3 defeat to Cambridge United in the play-offs; with Morison scoring twice at Broadhall Way, but missing a "gilt edged" chance in the return leg.Subsequently, activating a release clause in his contract, Morison was allowed to leave and, shortly after, agreed personal terms with League One team Millwall in May 2009, with a fee of £130,000 being agreed for the transfer.During his three-year tenure at the club, Morison made a total of 152 appearances, scoring 89 goals.