Willo Flood will consider quitting Celtic if he fails to win regular first-team football before the end of the year.
The Irishman - Gordon Strachan's final signing as Hoops boss back in January - made a rare start in Saturday's 2-1 friendly defeat at former club Manchester City.
Flood, 24, struggled to win a first-team place under Strachan last season and appears to have fallen further down the pecking order under new manager Tony Mowbray.
Flood, who joined boyhood idols Celtic from Cardiff after 18 months on loan at Dundee United, said: "If you go from playing week in, week out to being a bit-part player, it can be frustrating. You get frustrated with yourself and things around you. But I'll need to keep my head down and see what happens in the next couple of weeks.
"I had the chance to fulfil my boyhood dream of playing for Celtic. I couldn't turn it down and I have never regretted it.
"It's too soon to do anything right now. I'll keep my head down and hopefully catch the manager's eye. But if I'm not involved by January, I will have to go in and speak to the manager about my situation.
"I want to be playing games rather than sitting on the bench. Any footballer who says he's happy sitting on the bench lacks ambition.
"It was the same for me at City. I was involved under Kevin Keegan but when Stuart Pearce came in I never played as much as I wanted.''
Despite his lack of involvement, Flood is hoping to play a part in Celtic's glamour European tie with Arsenal.
He said: "I played against Arsenal twice when I was in England and it will be a big test for us. But the boys showed in Moscow that this is a team that can go places and get results.
"If we can keep it tight and keep a clean sheet, we have every chance of going through. They don't have a great image of Scottish football down in England.
"It's a better standard than they think and Celtic would surprise a lot of teams down in England.''