The Scotland midfielder has been battling an ongoing hip problem this season but recently it has started to show positive signs which Lennon did not think possible a few months back when an operation was an option.
"We thought it would deteriorate rather than improve," he said.
"We're not saying he's over the worst but he's had this since August and at times has played fantastically well.
"He has moved a lot more freely since his last injection and he keeps on going.
"Surgery is the last resort and is not 100 per cent guaranteed to remedy the problem.
"If we can avoid it then great, we'll shut him down at the end of the season and give him enough rest to recuperate fully."