The Hoops have dominated the domestic game in Scotland in the wake of financial struggles endured by their Old Firm rivals at Ibrox.
Seven successive Premiership titles have been secured, with many of those crowns captured at a canter.
The 2018-19 campaign is promising to pose more of a challenge, with Celtic having already dropped eight points to sit sixth in the table.
A 2-1 defeat at Kilmarnock last time out has seen some uncomfortable questions asked, with former star Commons of the opinion that those at Parkhead have hit a serious slump.
“The football they have played has been so dull and boring. It has been absolute dross - enough to induce a bout of narcolepsy.
“They aren't offering the fans any entertainment whatsoever. There is no flair. As a unit, the team looks so rigid and, individually, the players don't look like they're enjoying it.”
Commons added: “Celtic have only scored six goals in their six league games so far - and three of those came against newly promoted Livingston.
"That is dreadful. Meanwhile, you have Rangers sticking five past St Johnstone in one game - with five different players on the scoresheet.
“There was some chat a couple of weeks ago about how Rangers had made their worst start to a league campaign in 29 years. Newsflash: Celtic are actually below them in the league table.
“What we have on our hands is a highly competitive league, with so many good teams capable of taking points off each other on any given day.
“For the first time in seven years, it looks like we actually have a genuine title race on the cards. That is testament to what Steven Gerrard has done at Rangers.”
Commons believes it is now up to Rodgers to “rattle a few cages”, with a lack of attacking spark of serious concern to a side that has grown accustomed to sweeping rival outfits aside.
“The goal drought would really worry me,” added a man who won five league titles during his time in Glasgow.
“[Gary] Hooper and [Anthony] Stokes used to score 20-25 goals per season... each! Before that, you had Henrik Larsson, Chris Sutton and John Hartson all doing likewise.
“This current Celtic team simply aren't creating enough chances for anyone to get even remotely close to those kind of numbers.
“When Leigh Griffiths is fit and on form, he is without a shadow of a doubt the best goalscorer Celtic have. But something isn't right behind the scenes.
“It all looks far too nicey-nicey. I'm not sure there are enough big personalities in that dressing room who would really have the bottle to have it out with each other and rattle a few cages.”