West Ham boss Slaven Bilic admits he is worried by this weekend's game at Crystal Palace having had so many of his players absent on international duty of late.

Seven members of Bilic's squad were involved in international matches over the last ten days after drawing 2-2 with reigning champions Chelsea.

The Hammers are just one point outside of the Premier League top four and host an out-of-form Palace side who have not won a league game since December 19.

Despite being heavy favourites for Saturday's London derby, Bilic believes his squad's lack of preparation and rest means the game has come too early for West Ham.

"This international break, on one hand we didn't want it because we had that momentum and we want things to continue and keep coming because we were buzzing," he said.

"On the other hand, because we played many games it was not bad for us, we rest a bit and we train hard and after that we rested again.

"Some players went to play international games, we are still not back totally and that is why this game against Crystal Palace is coming too soon.

"I'm not happy because we will not be all on the pitch, some of the guys are coming back tomorrow, this game on Saturday is worrying.

"Some players are coming back tomorrow - Cheikhou Kouyate, Victor Moses and Enner Valencia had a long trip, (Dimitri) Payet is back from France, it is not ideal but we will have to get back immediately into the shape that we were before the international break."

Although he has his concerns, Bilic - who managed his native Croatia for six years - insists he is always happy to see his players go off and represent their country.

"You don't have your players until a couple of days before a game - but I always welcome when my players are called for international duty," he said.

"It gives them another dimension, it gives them confidence and they are more quality players than players not being called up.

"There are some pluses and some minuses, of course you would like your players to always be with you but if they are good players and you want them to improve and gain confidence and quality then you should be happy when they play for their country."

With their impressive form taking them to the cusp of European qualification ahead of a move to the Olympic Stadium for the start of next season, West Ham have started to be linked with big-name players across Europe.

The likes of Zlatan Ibrahimovic, Wilfried Bony and Michy Batshuayi are just three international strikers linked with east London in recent weeks.

But Bilic has dismissed such talk as pure rumour - although he admits the club are closing in on the capture of highly-rated Valencia teenager Toni Martinez.

The 18-year-old has been prolific in the youth teams at the Mestalla but now looks set to move to England, as Bilic praised academy manager Terry Westley's role in the seemingly-impending deal.

"With Martinez, we are quite close," Bilic revealed.

"Terry Westley from the Under-21s has done a tremendous job if we finish it and we are close to getting one of the brightest talents from Valencia.

"All the other things that appear in the papers about big stars and new signings, it is all speculation.

"We are going to be active and we are doing some small things, talking and all that, but it is not like you read in the papers."