Rodgers refuses to say if Celtic board match his ambition
The Hoops manager said Celtic may have reached a glass ceiling in European football.
Brendan Rodgers was unwilling to say whether the Celtic board matched his own personal ambitions for the Scottish champions.
Rodgers has pressed for the Hoops board to bring in reinforcements this summer in a bid to improve the Hoops squad.
To this point, however, Odsonne Edouard remains the only new face at Parkhead after one of Rodgers' main transfer targets, John McGinn, opted to join Aston Villa on Tuesday.
Rodgers, who confirmed Daniel Arzani is set to sign for Celtic and that Emilio Izaguirre is poised to make his comeback, believes the Hoops could have hit a glass ceiling when it comes to achieving success in European football.
Asked if his ambition was matched by the board, he said: "I wouldn't answer that. It's private."
On Celtic facing a glass ceiling in Europe, he added: "It's something that maybe is the case.
"But, for us, all we can is our very best with the resources we have.
"This is a wonderful football club with a worldwide, fanatical fan base and we want to bring as much happiness to them as we can with what we have.
"And I think we have done that these last couple of seasons.
"Of course, you always want that ambition to improve and be better, that may not always be the case but we always hope we can do.
"This group have shown they are developing but especially in the European side of the game, financially it is becoming more difficult.
"This season will demonstrate that, especially in this competition, no matter where we finish in it.
"The football landscape has changed dramatically in the last few years and that is mostly financially."
He continued: "It's always going to be difficult unless you have major investment, that's the reality of it.
"My ambitions for Celtic are to be the best it can be and the players to be the best they can be, that's where my ambition lies.
"I've huge respect for the people that work here at the club. They've created a very stable foundation, I have to respect that.
"Of course, as a manager I want the club to be the very best it can be and see the club progress.
"All we are looking to do is replace the players we want and improve the quality."
Celtic lost out on McGinn but Rodgers wished the Scotland international all the best for his move south.
He added: "I've seen him develop into a first-class young player.
"As a Celtic supporter himself, I would have loved for him to have been here but it wasn't to be.
"I spoke to him yesterday and wished him all the very best. He's joined a great football club and I'm sure he'll do very well for Steve."
Celtic face Hearts this Saturday and Rodgers expects Craig Levein will leave the grass long at Tynecastle once again.
He said: "I'm sure the grass will be long, but you have to play whatever is in front of you or at your feet.
"For me, it's about football and bringing the best game to the supporters, that won't change."