Reports emerged earlier this week that Lavezzi's uncle Jorge had been found shot dead in Argentina.
Despite the loss, Blanc says the 28-year-old has been training with the squad and is in contention for the fixture on Friday, as PSG look to increase their lead at the top of Ligue 1 to eight points.
"I will discuss it with him, if he wants to discuss it with me," Blanc said.
"He is normally training. I know he has been affected by personal death. That's it.
"We'll see with him. I count on him, he is fit to play. He is part of the group."
Friday's game will be PSG's 10th since the turn of the year, and Blanc says elements of fatigue are creeping into his squad, but that it is something they will have to deal with.
"I don't think it's physical tiredness," he said.
"I think it is mental tiredness. It is tiredness, of course. We must try to regain that freshness.
"We will not complain. I'm not complaining. We play every three days since January, we were prepared for that.
"My concern at the moment is to prepare the best possible team to win against Valenciennes."
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