The Liverpool legend believes another Brazilian in the squad will be a good thing for their star man.
The Brazilian enjoyed a fine spell in the second half of last season, becoming the club’s standout performer as he scored a number of impressive long-range efforts that caught the eye.
He has started this season in similar form, with a late winner against Stoke City in their opening game of the season suggesting that he is keen to carry on where he left off last year.
And Rush says he has developed into a big player for Brendan Rodgers' side, claiming he looks different to the player that first arrived at Anfield in January 2013.
"Coutinho is really starting to stand out now and he plays with a lot more confidence within himself," Rush told Sky Sports.
"He looks different now. He looked like a little boy when he came in, even though his quality was obvious, but he's a man now who knows what he has to do on the pitch. He puts himself into the tackles now. He doesn't shy away or anything.”
Firmino signing will only help Coutinho
Coutinho faces competition in the Anfield squad this season, though, with summer signing, and fellow Brazilian, Roberto Firmino having been brought in from Hoffenheim.
Both like to play in the number ten role behind the striker, with Coutinho known more for his passing game while Firmino is being eyed up as a player who can get Liverpool some much needed goals from midfield.
Indeed, the latter impressed while in Germany and has been a star for Brazil in recent times, with there great expectation on his shoulders from the Anfield faithful. While the competition between him and Coutinho could be seen as a negative, Rush believes having a fellow countryman in the squad will only be a good thing for Liverpool’s star playmaker.
"Coutinho's learned a lot from playing in the Premier League for the last couple of years,” he added.
“He's maturing as a person and as a player but he's still only young. I think the arrival of Firmino has helped him as well. Having another Brazilian around is good for him and I am sure they will help each other."