Buttler missed the Fourth Test, which India won by 157 runs, while on paternity leave, with Jonny Bairstow taking the gloves in his absence.
India’s victory meant they secured a 2-1 series lead ahead of the final Test in Manchester.
England had re-claimed momentum in the series with their victory in the Third Test but Rohit Sharma’s century and India’s bowlers turned that around.
Leach’s inclusion means England may opt to shuffle their attack, with James Anderson, Chris Woakes and Ollie Robinson looking weary. Mark Wood is also in contention after injury.
“We have got some aching bodies, I’m not going to deny that,” England coach Chris Silverwood said.
“We obviously have to keep an eye on that. (Wood) could come back and if he does, he will obviously add that pace for us.
“If the pitch is abrasive as it usually is at Old Trafford there should be reverse swing.”
Silverwood pinpointed Jasprit Bumrah’s second-innings spell as a game-changer, taking two wickets with reverse swing as England lost 6-4.
“We have to recognise situations first and foremost,” Silverwood said. “The spell from Bumrah was as good a Test bowling spell as you are going to see but at the same time if we want to be where they are we’ve got to manage those situations.
“He blew us away with that spell and made it very difficult for us but it is certainly something that we have to learn and that is what being ruthless is being all about.”