Smalley missed the 1-1 draw with Morecambe with a hamstring injury which the club confirmed will keep him out for the next two weeks and he joins four other first-teamers on the sidelines.
Lewis Montrose's hamstring strain has ended his campaign while Peter Leven, Justin Richards and Tony Capaldi look set to miss the final five matches of the npower League Two season.
One positive on the injury front was Jon-Paul Pittman's return to the matchday squad for the first time in four months on Friday.
Teenager Callum O'Dowda joined the striker on the bench, his first appearance in the 18 since the FA Cup clash with Sheffield United in January.
United's failure to win their last three games has dented their hopes of a late push for the play-offs.
- Sports & Recreation
- Peter Leven
- Lewis Montrose
- Tony Capaldi