Whithouse previously wrote the episode 'School Reunion' in 2006 and returned for the most recent series to script sixth instalment 'The Vampires of Venice'.
The writer recently attended a panel at this year's San Diego Comic-Con. According to SFX, when asked if he or fellow panellist and Who writer Paul Cornell would be contributing to the next series, he replied: “We’re contractually not allowed to say.”
Another panellist, novelist China Miéville, reportedly replied: “We can apply a bit of detective work here. If Toby’s contractually advised not to say anything, that must mean he’s under contract.”
Whithouse refused to confirm or deny the speculation.
It was previously reported that Cornell and former Who writer Tom MacRae may both be returning to the series.