The England international made his first appearance for the German as a late substitute in the 1-0 win over Swansea, only his fourth appearance since April after a hip operation and knee and foot problems.
Now Klopp has his two first-choice strikers available and Rush believes the Reds boss has decisions to make as although he has played with one up front, the Welshman sees no reason why both cannot be accommodated.
“All great players can play together. I don’t believe this great myth that they can’t play,” Rush, scorer of 346 goals for the Reds, said at an event to promote Liverpool Legends’ match against their Australian counterparts in Sydney on January 7.
“But how I look at it is you are now not guaranteed a first-team place.
“When Liverpool have been successful it was because you were not guaranteed a place.
“When the team is winning (the manager) is thinking ‘If I change the side here it might go there’.
“Competition for places is very healthy so give the manager a problem, make yourself available for selection – that is what all manager’s want, all players fit.
“If they are fit and available then the manager has to choose and that is what happened when I played for Liverpool.”
Christian Benteke has scored three times in his last seven matches – including a brilliant strike against Bordeaux last week – having been sidelined with a hamstring problem. Rush believes the Belgium international will get better as he gets even fitter.
“I was really happy when we signed him. He can play up front by himself, alongside someone and is a different option there and we’ve not had that previously,” he added.
“We had (Philippe) Coutinho, (Roberto) Firmino, (Adam) Lallana and now you have Benteke and that is a good thing.
“He will get fitter and will get better and the goal he scored against Bordeaux showed what he can do.”
Victory over Swansea put Liverpool within six points of Premier League leaders Manchester City but Rush, who won two European Cups, five league titles, five League Cups and three FA Cups with the club, believes the players have to concentrate on securing a return to the Champions League and possibly winning silverware this season.
“What’s realistic is to finish in the top four but it would be great to win a trophy for the supporters,” he said.
“We signed a few players in the summer and the likes of Benteke could be the difference between fourth and fifth.
“But every competition you play in you want to win. You shouldn’t go into it if you don’t expect to win.
“They are in the quarter-finals of the Capital One Cup (on Wednesday) and Southampton are difficult but they can beat them.
“Realistically it is most probably their best chance of winning a trophy but it is knowing how to do it.
“You say you’d like the game to be at home but we’ve been playing better away so I think it is a good chance now.”