The Blues were already controlling the game with three goals inside five first-half minutes before Lampard was given his marching orders for appearing to slap Luis Boa Morte.
The referee's assistant told referee Peter Walton Lampard's hand connected with Boa Morte's face and the midfielder was given a straight red card.
But manager Grant will wait for video evidence before deciding whether to appeal against the decision.
Grant said: "The assistant referee said that Frank slapped the face of Boa Morte. If it is true, I think the rule is that it is a red card. If not, maybe someone else needs to get a red card.
"I will wait to see it but if the assistant referee is right, it is a red card. I have not asked Frank about it."
Hammers boss Alan Curbishley believes Lampard's dismissal was a little harsh and argued the referee could have applied common sense in this instance.
"As they have both got up, I think Frank has pushed Luis but sometimes you look at that and like to think common sense might prevail," Curbishley said. "But the referee sees it instantly and makes a decision. He decided to send him off. I don't know if Chelsea will ask him to have another look at it but it was a soft one."