Manuel Pellegrini says Declan Rice should not be pressurised into making a decision on his international future.
Rice was not named in the Republic of Ireland squad on Thursday and is still considering his international future.
Asked if Rice had sought his advice, Pellegrini said: "I am always talking with all the players, Declan also.
"He is a young player and we need to give him time to make a difficult decision. We must not pressure him about which country he will play for. He needs time.
"He can be a top player. He is learning a lot and always listening and asking what he can improve. He is very young but has a huge future."
Things are starting to look a lot brighter for Pellegrini and West Ham, who are unbeaten in their last four games and have moved up to 14th in the Premier League.
The Hammers travel to the Amex Stadium on Friday, live on Sky Sports Premier League, to face a Brighton side who beat them both home and away last season, scoring six goals in the process.
"The past is the past," said Pellegrini. "Every game is different so I don't think that matters.
"Brighton are a team that plays with a lot of intensity. They have been working with the same manager for a couple of seasons, so we must be aware of them. We always expect a difficult game against every team, for different reasons.
"In the Premier League, every game is different. Brighton also beat Manchester United and they are at home so we have to be very clear in the way we approach the game."
Pellegrini will be without Javier Hernandez against Brighton as he recovers from glandular fever while midfielder Carlos Sanchez requires an operation on his injured knee.
Andy Carroll is back in light training after ankle surgery but Pellegrini says he "needs a couple of weeks more" before he can be considered for selection.
Marko Arnautovic has been starring in attack during Carroll's absence and scored his fourth goal of the season in last Saturday's win over Manchester United. The Austrian has been playing through the pain barrier after bruising a bone in his knee.
Asked if Arnautovic should have been switched from winger to centre-forward earlier in his career, Pellegrini said: "Maybe he was a No 9 who was playing as a winger! Now he returns to the position and needs to make different movements to create space.
"Marko has a lot of power and he will also keep improving because he can give more. He can score more goals and must have a complete season.
"He has some problem in his knee but he has started the season well. To be a top player, you must try to score in every game during the whole season."