The Hoops will head to Belfast after conceding 12 goals in four friendly defeats in Germany and with a number of key players absent due to injury.
Lennon said: "It's so early, it's a harsh reality of where we are.
"We won the cup final at the end of May and we are back in on the 24th of June.
"It's been staggered and a bit disjointed because we have had a lot of injuries as well.
"Matthews, Ledley, Twardzik and Hooper have hardly featured and obviously we have lost Victor (Wanyama).
"They are the ups and downs you have to cope with during pre-season but I don't think you'll see us anywhere near our best for another two weeks or so."