Marian Shved will miss Celtic's Champions League qualifying clash with Sarajevo on Tuesday.
The Ukrainian international's much anticipated competitive Hoops debut has been put on hold again after he suffered a training ground knock on Monday.
Jack Hendry will also miss out after he also suffered an injury ahead of the the Hoops' Euro opener.
Shved has made a fast start at Celtic was named in Lennon's starting XI for the game against St Gallen last week in what was a dress-rehearsal ahead of their trip to Bosnia.
There's better news for Hoops fans as new arrivals Christopher Jullien and Boli Bolingoli-Mbombo were on the plane ahead of the season opener.
Celtic are aiming to return to the group stage after missing out last season and Lennon is backing his players to rise to the challenge.
He said; "The players are in as good condition as can be for this stage of pre-season."
"The Champions League is always important to Celtic. We have a difficult tie but the players know what the incentives are and they know what's at stake."
