The club skipper is set to return at Stamford Bridge on Tuesday having been kicking his heels since being sent off 14 minutes into Chelsea's shock opening day Premier League defeat by Burnley, resulting in a three-match ban.
Last season Cahill, along with his Chelsea team mates, had to watch the Champions League from the sofa after failing to qualify when they finished a woeful 10th the season before.
He will need no firing up the against the Champions League debutants from Azerbaijan.
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"I'm delighted to be back available for selection, I'm itching to play and getting back involved with the rest of the squad," Cahill, who did play two games for England in that period, told a news conference on Monday.
"It's been frustrating for me being out. But it's about the team doing well and they've done alright."
The match will have added meaning for Cahill after being forced to watch the competition on television last year owing to Chelsea's 10th place finish in the 2015-16 season.
"We feel we're back where we belong. Which is amongst some of the very best teams and we're looking forward to testing ourselves. Everyone realises that was a freak season for us.
While Qarabag look like being the whipping boys of Group C, Chelsea's other opponents are seasoned European heavyweights Atletico Madrid and Roma.
"It's a difficult group, but that's the calibre of teams you're coming up against the Champions League," Cahill, part of the Chelsea side that won the tournament in 2012, said.
"But we're more than capable of competing at this level. As a group it'll be interesting to see how we get on. We have quality throughout this squad, but we're looking forward, we're excited by this competition.
"We're excited to be back involved. It's the biggest stage to be involved in club football."
(Reporting by Martyn Herman; Editing by Toby Chopra)
