Doyle was released from international duty with the Republic of Ireland this week because of a recurring knee injury.
Club-record signing Fletcher stepped into the breach and scored five goals in five games when Doyle was initially sidelined with the problem for the final two months of last season.
The former Burnley player said: "My aim is to pick up from where I left off at the end of last season in terms of performances.
"I had a good finish to the season and, if I can get amongst the goals again, I'll be happy. I hit double figures in the league last season and that's usually the aim I start with."