Firmino has been sidelined since the start of November with a hamstring injury, but recently returned to training with the Liverpool squad at Kirkby.
It is a welcome boost for the Reds, particularly if Mohamed Salah and Sadio Mane depart for the Africa Cup of Nations next month, with Firmino having scored six and assisted one in 11 games already this season.
Ahead of the visit of Newcastle on Thursday night, both Firmino and Jones took part in a training session under the lights, the latter back after six weeks out with an eye injury.
And speaking in his pre-match press conference, Klopp confirmed that his No. 9 is back “in contention,” while it is “good news” when it comes to the return of him and Jones.
“Bobby trained completely normal yesterday, so I would say he is in contention,” he told reporters.
“Curtis had his first partial session with the team, so he’s not far off.
“Timing-wise could not be better, getting two players back of this calibre is obviously good news. So that’s it.”
In fact, the Reds were also boosted by the return of Diogo Jota to training on Tuesday, with the forward having missed the last two games against AC Milan and Villa with a knock.