The former Celtic attacker is worried new signings aren't making an impact.
The Hoops suffered a major European shock on Tuesday night when they were dumped out of the UEFA Champions League at the hands of Cluj, who operate on a much smaller budget than the Scottish champions.
Celtic have enjoyed incredible domestic success over the last decade but, having failed to reach the group stages of the Champions League in four of the last six years, serious questions are being asked about the direction of the club.
Commons' big worry is that the players they are signing don't appear to be forcing themselves into Lennon's plans, even in massive matches.
As quoted by The Scottish Daily Mail (15/08 print edition, page 83), he said: "There are also question marks over why a new £7m defender, Christopher Jullien, couldn’t get a game either.
"It’s a real worry that Celtic are investing heavily in players who are not making an impact.
"The players coming through the door at Celtic these days don’t tend to fill you with much confidence."
The French defender arrived at the Hoops in June and has had two months to get up to speed in Lennon's side. Why is he not featuring? Commons is right to raise it as a bit of puzzle.
Jullien is one example, but the failure to play Boli Bolingoli on Tuesday also raised eyebrows.
Lennon instead opted to pull stand-out Callum McGregor from his midfield position to play at left-back, depleting the Hoops' strength in the middle of the park.
Both Jullien and Bolingoli have plenty of time to make an impact, but the early signs must be concerning for some supporters.
With just a few weeks remaining before the end of the summer transfer window, time is running out on Celtic making the signings they need to compete at home and abroad over the coming campaign.
Have something to tell us about this article?