Transfer-listed Johnson's displays for the reserves at the start of pre-season have earned him the praise of boss Gary Megson and a recall to the first-team squad ahead of the new campaign.
The bookmakers rate him as the 12/1 third favourite behind Marcus Stewart of Bristol City and Luke Beckett of Oldham to top the League One scoring charts.
Gareth Taylor is a 16/1 chance with Scott Dobie and Neil Harris priced at 20/1.