Roberto Firmino
Both Manchester United and City were previously been linked with Roberto FirminoGetty Images

Former Liverpool midfielder Didi Hamann says manager Brendan Rodgers "will have made the club's best business in a long time" if he sanctions the departure of Raheem Sterling for £50m ($78.5m) after signing promising Brazilian talent Roberto Firmino for almost the half the money.

The Premier League giants announced the arrival of the Brazil international to Anfield after, according to the BBC, they agreed to pay Hoffenheim around £29m to follow the summer additions of midfielder James Milner, striker Danny Ings, goalkeeper Adam Bogdan and promising defender Joe Gomez.

Even though Firmino is proving to be one of the sensations of the Copa America with Brazil, some believe Liverpool have overpaid to secure his services, in what happens to be the second biggest transfer in the club history – after the arrival of Andy Carroll from Newcastle United for £35m in 2011.

But having monitored his development while working as a TV pundit for the Bundesliga in recent years, Hamann has hailed his addition and urges Rodgers to follow it with the sale of Sterling to complete a transfer masterstroke.

"If Liverpool get £50m for Sterling and invest half that money in Firmino, the club will have made their best business in a long time – probably the best bit of business since Liverpool managed to sell Jason McAteer to Blackburn for £4m!" Hamann said to Liverpool Echo.

"I've not got a problem with the money Liverpool have paid for Firmino. This is a Brazilian international whose best years are well ahead of him, not behind him. He's one of the up and coming stars in Brazil and I think he's worth it.

"Coming to Anfield will be a step up for him but I think he's ready for it. Look at what other clubs are spending. To attract the best, you have to pay big money."

The former Germany international said Firmino's signing is a "statement of intent" for the club but still hopes Rodgers will complete the summer overhaul with a few more players.

He said: "To be honest, he's the type of player I thought Liverpool wouldn't be able to get without Champions League football. To get him is a real statement of intent and hopefully there will be two or three more big signings to come.

"I think people have been a bit disheartened over the past six weeks or so. Expectations had gone down and I was worried that Liverpool would go into the new season on a low. We've needed a spark from somewhere and this signing has given supporters the boost they needed."

Meanwhile, the Liverpool Echo reports the Anfield club are also on the verge of completing the signing of Nathaniel Clyne after Southampton accepted their improved offer of £12.5m for the right-back.