Neymar has been forced to undergo surgery, which rules him out of the second-leg of their Champions League tie with Real Madrid.
Lucas told SFR Sport: "If he chose to have surgery, I think it's the best decision. Only he can decide. He has to think about the World Cup. He wants to arrive at 100%. I went through that too.
"I hope he will come back well, that he will recover well. It's hard when you get hurt and you cannot play, especially when there are important matches and a World Cup coming up.
"But I'm sure he will come back stronger and at 100%."