Gerrard has finished his first season with Major League Soccer side LA Galaxy who he joined after 17 years at Anfield, and has been training with his old team mates.
"It's a good situation. Everybody had a smile on their face when they saw Stevie," Klopp told a news conference on Tuesday.
City, Liverpool turn eyes to League Cup prize
"It's good to have him here and we hope we can help him, and he can help us for sure with being in the dressing room. It's cool."
Gerrard, 35, is highly unlikely to re-join the club on loan, but Klopp said having him around was a boost.
"He won't play (against Southampton), but he was in good shape!" Klopp said.
"I said to the team before training, when Stevie was with us in the dressing room, that it's completely normal and it should always be like this -- if you're a player like Steven Gerrard in Liverpool then the doors always have to be open. That's how it is at this moment.
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"For us, it's a good situation because he was a very important player at this club, and at this moment he is a very important player because he is in training."
The League Cup represents an early chance for Klopp to deliver his first silverware at Anfield, having taken over from Brendan Rodgers in October.
He is expecting a tough game on the south coast, though.
"The biggest fault you can make is think about the next round," he said.
"Only Southampton. They're pretty hot on this game, they've lost their last two games and they want to strike about.
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"I hear Southampton and Liverpool are not the best friends, so it will be a feisty game.
"The quarters is still far away from the final. But I'm excited and looking forward to the game. I can't say yet what team I'll play."
He did confirm that Adam Bogdan would take over from Simon Mignolet in goal while Daniel Sturridge and Jordan Henderson will be in the squad having returned from injury as substitutes in Sunday's Premier League win over Swansea City.
Playmaker Philippe Coutinho, who has been missing with a hamstring injury, faces a fitness test.
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