Salah back in Liverpool squad after AFCON
A smiling Salah was put through his paces at the club's training centre with the rest of Arne Slot's squad ahead of Wednesday's match in France.
The return of the Egypt forward has been a major talking point after he took aim at Liverpool in an explosive interview early last month.
Salah accused the club of throwing him "under the bus" after he was benched for three games in a row and said he had no relationship with Slot.
But he appeared as a substitute in a 2-0 Premier League win against Brighton on December 13, providing an assist, and Slot subsequently said the club had moved on from the furore.
Last week, Slot said he welcomed Salah's return, refusing to divulge the content of his conversations with the 33-year-old, whose team finished fourth at the Africa Cup of Nations.
Slot said before Saturday's 1-1 draw against struggling Burnley he was unsure whether the forward would face Marseille.
But on Tuesday afternoon Liverpool said Salah had been named in the 20-man squad for the trip to France.
"Mohamed Salah is included having returned to the club after representing Egypt at the Africa Cup of Nations," a statement on the club's official website said.
Liverpool are currently ninth in the league phase of the Champions League.
The top eight qualify automatically for the last 16 while teams placed from ninth to 24th face a play-off round.
Salah is Liverpool's third-highest goalscorer of all time with 250 goals in 421 appearances, winning two Premier League titles and the Champions League since joining from Roma in 2017.
He signed a lucrative new two-year contract last year as he played a starring role in guiding Liverpool to a record-equalling 20th English top-flight title.
But he has been a shadow of his former self during Liverpool's struggles this season, managing just five goals in all competitions.
Liverpool's Premier League defence collapsed with a run of six defeats in seven matches starting in late September.
The club are now unbeaten in 12 games in all competitions but remain 14 points behind Premier League leaders Arsenal.