Spurs are also sweating over the fitness of Tom Huddlestone and David Bentley as they look to maintain their push for a top-four finish.
Spurs boss Harry Redknapp has admitted Lennon has been told to rest for six weeks before stepping up his recovery.
"David Bentley has a tear in his groin and Lennon's got to rest for six weeks," said Redknapp. "We are picking up a few knocks to key players."
Redknapp also revealed Jermaine Jenas, who has missed the last four games with a long-standing groin problem, is set to go under the knife this week to solve the injury.
"Jenas looks like having an operation on Wednesday," added Redknapp.