Thiago has missed Liverpool’s last three matches due to a hamstring issue and Firmino has not featured since scoring in the last-16 first-leg win at San Siro because of a muscle injury.
Meanwhile, illness meant Matip was unavailable for Saturday’s 1-0 victory over West Ham United.
However, Klopp has confirmed the trio resumed full training on Sunday, with the boss also reporting no fresh fitness concerns ahead of the Anfield meeting with Inter.
“I think all trained yesterday fully. I’m not sure yet what we make of that exactly, to be honest, because we have to see how they react,” the boss said on Monday.
“So, Thiago was only a week out, probably will be fine but we have to wait for it. Joel was only three or four days I think, so he is fine, I would say.
“With Bobby, it was longer out, it was [his] first session, so we have to see if we have to stress that or if it makes probably sense to give him just a few more days with proper training.
“Because we obviously don’t train properly today, it’s a minus-one session, it’s tactical stuff, not high intensity and Bobby might need something else. We will see that.
“But they are all in training.”
Visitors Inter will be without suspended midfielder Nicolo Barella as they seek to overturn a 2-0 deficit in the second leg, but head coach Simone Inzaghi told the media that he has an otherwise-full complement to choose from.
Last match
Liverpool 1-0 West Ham (March 5): Alisson, Alexander-Arnold, Konate, Van Dijk, Robertson, Fabinho, Henderson, Keita, Salah, Diaz, Mane.
Inter 5-0 Salernitana (March 4): Handanovic, Skriniar, De Vrij, Bastoni, Dumfries, Darmian, Brozovic, Barella, Calhanoglu, Martinez, Dzeko.