Wolff has been steadfast in his support of Antonelli, who he fast-tracked into Formula 1 this year at the age of 18 as a replacement for Lewis Hamilton, following the seven-time champion's move to Ferrari.
Last weekend at the Dutch Grand Prix, Wolff effectively confirmed that both Russell and Antonelli would stay at the team next season.
But Antonelli has had an up-and-down first season in F1.
He took pole for the sprint race in Miami in May, following that up by beating Russell in qualifying for the grand prix as well.
Antonelli scored a maiden podium in Canada in June, but lost confidence following a change in the Mercedes rear suspension design.
He said he felt better in the car once Mercedes reverted to their previous suspension for the Hungarian Grand Prix two events ago, but has still struggled for consistency.
Antonelli made an error in crashing out with Charles Leclerc's Ferrari in Zandvoort, and followed that with another messy race at Monza, where in addition to his other incidents, he also spent six laps passing the Alpine of Pierre Gasly after his pit stop.
Wolff said Antonelli needed "a clean weekend", adding that meant "almost not to carry too much trauma of previous mistakes into the next session or into the next weekend because that is baggage.
"You're not going to attack the corner hard if you've been off there before and it finished your session, or maybe you're not attacking a driver that should not be in your way like Gasly because he had this situation with Leclerc.
"Kimi shouldn't lose even a second on Gasly."
Asked how to do this, Wolff said: "Just freeing him up. Freeing him up. You know, he's a great driver. He has this unbelievable ability and natural talent. He's a racer. It's all there. But we need to get rid of the ballast."