Celtic manager Neil Lennon has hinted that the club is unable to compete financially with other sides in the Champions League.
The Scottish Premiership side opened up their Group H campaign with a 2-0 defeat to AC Milan on Wednesday evening.
Lennon has claimed that due to a paucity of funds, his side lack "a Champions League goalscorer."
"What do you class as a Champions League goalscorer? Van Persie? Well they cost £20m," he told BBC Sport. "We don't have £20m or £30m to spend on a striker like that.
"Of course we lack a Champions League goalscorer. Messi? Ronaldo? Shevchenkno? They're proven Champions League goalscorers, you just don't buy them.
"We've lacked a Champions League goalscorer since I took over. We haven't had that since Henrik Larsson. They cost a lot of money and they're hard to find."
Celtic face Barcelona in their next Champions League match on October 1.