Silva marshalled the Chelsea defence to a clean sheet in their 0-0 draw with Sevilla in the Champions League but took a knock when he landed awkwardly in the second half.
The veteran Brazilian finished the game and afterwards Lampard was quick to allay any fears over his fitness.
“He has not flagged it, so I think we are OK,” said Lampard, who praised Silva for his display at Stamford Bridge.
“I thought Thiago showed the things I have spoken about, his experiences and qualities. [Edouard] Mendy had one good save to make and he made it, and was good with his feet.
“Against a very good team it was a very organised defensive performance. I am very pleased.
“To get through the game will give us good confidence. We are going to get better. I keep saying the same thing but we have not had the personnel in there playing regularly, getting relationships and working off each other. The more we do that then we will get better naturally.”
Chelsea will travel to Old Trafford to face a Manchester United side on a high after their 2-1 win against Paris Saint-Germain in the Champions League.
Lampard told BT Sport: “They had a really good result. We have to. It is a long season and we are in the early stages of it. Manchester United is going to be a huge test, off the back of a very good result for them. We have to go there with belief.”