Redknapp: Lennon World Cup hopes in balance
Lennon, whose form up until December appeared to have cemented his place in Fabio Capello's squad, is making slow progress in his recovery from a groin injury.
"I hope he's going to be OK. I hope he'll play for us before the end of the season. He's desperate to get fit," Redknapp told the BBC on Sunday.
"It must be frustrating for Aaron. We just can't get him right. He's been back to the specialist. We're taking our time again, building up his strength in the groin area.
"He could suddenly see a bit of light and come back and if he does then he could be ready (for the World Cup). Four or five weeks, we'll have to wait and see."
Lennon last played on December 28.