The Argentine has started each of the last three games under Moyes.
Lanzini has missed 39 games in all competitions for West Ham due to injuries since the start of last season. The Argentine is now fully fit, having played a part in each of the club's last six games in the Premier League.
The 26-year-old is slowly getting back to his best and Moyes hailed his recent performances and claimed that the club are pushing him hard to get him back on top form.
He said: "We've got really close affection to Manu because of how well he played for us last time and we saw the standards he can get to. We're not expecting when he's below those. We're pushing him hard. We need him.
"He's one of our key creative players and he's one of the players who can make a difference. There's a really good player there and we hope we can get him back to top form."
When on form, Lanzini is one of West Ham's best players. The Argentine has the ability to turn games on its head almost single-handedly and with the quality of players around him now, he can help West Ham go up the table very quickly.
The Hammers are 17th at the moment, level on points with 19th place Watford. Moyes has a breather with respect to the Premier League thanks to FA Cup action this weekend but he will be hoping to get some confidence back at the club against West Brom.
Lanzini, should he start tomorrow, will be one of West Ham's most important players and he will have to do well to overcome a tough Baggies side who are flying at the top of the Championship.
Have something to tell us about this article?