PSG travel to the BayArena for the first leg of the last 16 meeting as the defending Ligue 1 champions look to improve on last season's run to the quarter-finals.
Cavani sustained a thigh injury in the 2-0 win over Bordeaux late last month and has missed PSG's last two games.
And Blanc effectively confirmed that the Uruguay international will be unavailable for Friday's league game with Valenciennes and the duel with the Bundesliga outfit, tipping the former Napoli man for a return in the game against Toulouse a week on Saturday.
"Edinson Cavani follows his program and should return at the end of next week. All the signs are very good," Blanc said.
However, Cavani's strike partner Zlatan Ibrahimovic should be fit for both encounters, despite struggling with back problems over the past week.
"Zlatan Ibrahimovic has trained normally for two days without any problems," Blanc added. "He is fit to play and will probably play against Valenciennes."
Former France coach Blanc admitted that he may reshuffle his team ahead of the encounter with Leverkusen, but is keen to stay focused on overcoming a relegation-threatened Valenciennes side that has won three of their last six league games.
"I think it will be a different team from the one that played Monaco," Blanc added. "But to prepare for the Leverkusen match, it will not be a bad thing to play against Valenciennes on Friday.
"The second part of the season began in Brest (in the Coupe de France), it does not start against Leverkusen. The championship is important, we must win against Valenciennes tomorrow (Friday)."
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