Izaguirre trained with his new team-mates on Wednesday morning after agreeing the move from Motagua in his homeland.
However, the 24-year-old will not be available for Thursday night's Europa League qualifier against Utrecht.
Sweden centre-back Daniel Majstorovic, who also signed this week, has taken the one available late spot in Celtic's Europa League squad.
But Lennon may play Izaguirre, who will compete with Charlie Mulgrew for the left-back spot, when Celtic host St Mirren in the Clydesdale Bank Premier League on Sunday.
Lennon said: "He trained today. He won't play tomorrow but should be available for selection after that.
"He's a good player. He's strong defensively, he's quick, he's got a very good left foot and he's good going forward.
"He had a good World Cup for Honduras. (Full-back) is an area we've been looking to fill for a while.
"We've taken our time with this one and we think we've got the right one."
Meanwhile, Lennon revealed that striker Ben Hutchinson could be going on loan to Lincoln City.