Pablo Zabaleta has admitted that speculation over the future of Marko Arnautovic and other West Ham players has created a "bad atmosphere" at the club.
Arnautovic's future has dominated headlines at the London Stadium, with the forward reportedly wanting a move to China before signing a new contract minutes after Saturday's FA Cup defeat to AFC Wimbledon.
The 29-year-old, who missed two matches in January, returned for their 3-0 loss to Wolves on Tuesday but limped off on crutches and is set to undergo a scan on a suspected foot injury.
Zabaleta feels speculation around Arnautovic and others has caused some damage after three straight defeats.
"Honestly, I think so many situations off the field have been creating a little bit of a bad atmosphere," said Zabaleta.
"I'm not just saying that is the only thing - because we lost two (league) games. I remember in December, when we had a good run, you could see West Ham playing as a team.
"In January, it's been tough on and off the field and the only good thing was the win against Arsenal.
"But the reality is if you want to be a better team and be in a better position then you can't go from beating Arsenal to losing three games against two mid-table teams and a smaller team in the FA Cup.
"I can't wait for February 1 and everyone is back on it again, we need commitment again from everyone.
"I understand January is a difficult month for clubs, because you can have big interest in your best players. But Arnie was out of the squad for two games, he's been the main player for us.
"When you see so much speculation around the team, players moving on, or some coming in, that can distract a little bit with the atmosphere in the dressing room, it's hard for the manager as well.
"I'm not saying it's all about Arnautovic, it's not only his situation. There have been many players, names around the media. If we want to become the team we were in December, then we need to bring everyone together and stick together."
Sky Sports News understands the Hammers are close to agreeing a deal with Celta Vigo that would see striker Maxi Gomez arrive in the summer.