Slaven Bilic has confirmed his interest in taking Borussia Monchengladbach midfielder Havard Nordtveit to West Ham, but says several clubs are in the race for his signature.
Gladbach confirmed earlier this week that Norway international Nordtveit would not be renewing his contract with the Bundesliga club in order to pursue a move to the Premier League.
West Ham have been tipped as the front-runners for his signature with Liverpool and former club Arsenal, for whom he did not make a competitive appearance, also said to be interested.
And Hammers manager Bilic says he is keeping a close eye on developments.
"Many clubs are interested in Nordtveit and monitoring the situation," he said at a news conference ahead of West Ham's Premier League contest at Chelsea on Saturday.
"We are also interested in him."
West Ham have won three straight Premier League matches and lost just one of their past seven - form that has left them just two points adrift of the Champions League places in fifth.
They next travel to Stamford Bridge to face a Chelsea side whose hopes of silverware this season ended after they were knocked out of the Champions League and FA Cup by Paris Saint-Germain and Everton.
But Bilic warned of a Chelsea backlash, adding: "They went out a couple of competitions last week.
"They were very positive so maybe they were more focused on the Champions League and the FA Cup but now they're out maybe it's harmed the confidence and atmosphere at their training ground.
"But on the other hand they are also thinking there's nine games to go and if they click they can finish very, very high also.
"In that sense it's not a great time because now they have only the Premier League and make no mistake I'm expecting them to be really hungry and totally focused on the Premier League."