West Ham boss David Moyes is confident Kalvin Phillips will prove himself.
The Manchester City midfielder has had a sluggish start to his loan.
But Moyes said: "We brought him in to to be to be a key player for us. I believe he will be. I think he is going to take a little bit of time just to get himself back up and running, but that's fine.
"I've got no problem with that.
"We've got good midfield players. He's in addition to them. I need him to supplement what I've got – help out through injuries and suspension, and hopefully he's form would mean that he is always a starter. We're happy to give them a bit of time and let him break his way in."