Samaras is coming to the end of his contract at Celtic Park and he has yet to agree terms on a new deal.
The likes of Atletico Madrid and Hull City have been linked with a move for the Greek international and Lennon wants the player to let him know if he plans to stay or go so that he can bring in a replacement should Samaras leave this month.
"We need an answer because that will define how the rest of the month will pan out," noted Lennon.
"We've given him time and he's been a great servant. It's been a tough few months for him.
"But he's had an opportunity to go home now, clear his head and come to a decision.
"There is other interest in him. I've not had direct contact with any club but through his representatives there is interest.
"We're hoping it's not a case of him staying and going in the summer.
"We've not made any bid on any strikers and a lot will depend on what happens with the two boys [Joe Ledley and Samaras] and where they want to be.
"We're in talks with one player and we're going to head home and put the pedal to the metal on a few things."
The player Celtic are in talks to sign is Stromsgodset midfielder Stefan Johansen, with Lennon hopeful of tying up a deal for the highly-rated Norwegian international.
"We've been in talks with his club and his representatives and hopefully we can get something sorted out in the next few days," added Lennon.
"I can't really put a time on that as I haven't spoken to Peter Lawwell since Friday, but we are well down the line on that one."