Brendan Rodgers won't allow Old Firm rivalry to affect friendship with Mark Warburton

The Ibrox boss called Rodgers when the former Liverpool manager was formally unveiled as Ronny Deila’s successor to welcome him to Glasgow – and the Hoops boss doesn’t envisage the friendship being undermined by his post at Celtic Park.

“We have a friendship that goes back a number of years so no matter how you people try to portray it, or might want to work it, this is a friendship that doesn’t change,” smiled Rodgers. “Obviously the clubs are rivals but he’s a good guy and it’s always nice to talk to him.”

Read more: Quality over quantity as Brendan Rodgers targets new additions

Meanwhile, Rodgers has insisted that he doesn’t have a wage ceiling under which he is working at the club.

He has been linked with a move for Joe Allan whom he worked with at Swansea and Liverpool - "Joe is a wonderful player I always look at all my former players,” said Rodgers, but he has maintained that he has not been told by the club hierarchy that he has a maximum budget at which salaries are capped.

“Every club will run on affordability and availability.

Read more: Rangers boss Mark Warburton insists Old Firm battle won't ruin his friendship with Celtic counterpart Brendan Rodgers

“I understand the market as well. I can’t go out and get Luis Suarez, I know that.

“But I know that the club will push to get the possible player that we can and that’s what they have done.

Asked if he had been told there was a cap on salary levels, Rodgers said: “No, the variety of wages within the squad will tell you that.

“In any of the meetings that I had, that was never spoken about.

“We are working on trying to maybe bring one or two in. The idea we want is quality, that's what we are looking for. You have to respect the current players are the Scottish Premiership champions. And if we can add to that and help them with one or two players, then that would bode really well for us.”

One of those areas could be an additional striker to pair with Leigh Griffiths.

“It's one of the areas,” said Rodgers. “Young Leigh was fantastic last season. To get 40 goals and carry that mantle throughout the season, he had an amazing season.

“He may not score 40 goals again this year but he is certainly hoping to be a very valuable player for the team. But he needs help.

“You have a 50-60-game season, trying to challenge in Europe as well as the cup competitions and the league, then you have to have a balanced squad, and that will certainly be an area we need to look at.”

Meanwhile, Charlie Mulgrew is reported to be considering a three-year offer from the club, but on reduced terms as to what he was on.

“He is a player I have spoken to,” said Rodgers. “A player we would like to keep of course. But that depends on how contract talks go. We had a real good conversation. I always liked Charlie, watching him from afar.

“Good balance, looked a good professional, a Celtic fan from what I hear – so the club means a lot to him. I think everyone respects as well that he is at a stage of his career where it could well be his last contract. I always respect that with older players at 29 or 30 years of age.

“This is arguably the most important contract of their life. So they have to take their time to assess that and look at that.”