Manager Habib Beye later explained that the forward was still struggling with an injury picked up against Lille a few weeks earlier.
Speaking before kick-off, Beye said Greenwood’s physical condition, rather than tactics or recent form, influenced the decision.
Despite scoring 25 goals in 41 appearances this season, the club chose caution to avoid worsening the issue.
"Mason we have looked at since the start of the week, he is very limited by the injury from Lille. It's been two games that he's played with a lot of pain, we can't put him in danger," said Beye.
Greenwood played the final 30 minutes but could not stop Marseille from drawing 1-1 at home.
