Petrov has had to play second fiddle to the Nigel Reo-Coker and Jean Makoun partnership in recent months.
But the Bulgarian international earned a recall for last week's win over Newcastle and Houllier has confirmed he will start at West Ham.
Houllier said: "I left him (Petrov) out when I felt it was maybe good for the team.
"But he showed a lot of commitment and his fitness has improved and he is a great captain also.
"In difficult times you need the people you can rely on and he is one of them. He is in my plans. I'm not talking about the past, I'm talking about the future."
Source: PA
Source: PA