The midfielder could be sidelined for a considerable amount of time after he was caught by a late challenge during Posh's 2-0 defeat.
Ferguson was unhappy with the challenge on his player, that the club fear has left the 20-year-old with damaged ankle and knee ligaments.
"Their player has done him like a kipper," he told Peterborough Today. "It was a horrible tackle and it looks like a bad injury.
"Danny was holding his ankle and then his knee and he left the pitch in a bad way, but we will see how he is."
Teenage midfielder Daniel Johnson turned home Eric Lichaj's cross to open the scoring and summer signing Brett Holman staked his claim to replace the injured Gabriel Agbonlahor when he slammed home the second with his left foot.