Eden Hazard believes Chelsea's problems this season are partly due to the team's participation in the Champions League.
Antonio Conte led the Blues to the Premier League title in his first season in English football, Chelsea having failed to qualify for Europe after finishing 10th in the 2015-16 campaign.
But with European commitments adding to their domestic duties, Chelsea have struggled to maintain their form from last season, sitting fourth in the Premier League after successive defeats against Bournemouth and Watford.
Chelsea were also beaten by Arsenal in the semi-final of the EFL Cup last month, with Hazard citing extra games as a reason for Conte's side finding life harder this term.
"I think the Premier League is difficult," he told ESPN FC. "It's hard to win every year.
"Last year we didn't have the Champions League. This year we have less time to be ready for the games. Every week there are three games."
Chelsea are also without two of their key players from last season, Diego Costa having returned to Atletico Madrid and Nemanja Matic being sold to Manchester United, while club icon John Terry departed.
Costa's replacement Alvaro Morata has lost form and been unable to stay fit, while midfield signing Tiemoue Bakayoko has failed to adapt to the Premier League, the former Monaco man sent off in a 4-1 loss at Watford on Monday.
"We changed a couple of things, we lost players, we brought some new ones and every year is different," Hazard added.
"That's why we love football - if there is only one team that wins it would be boring. That's why football is special. You never know what's going to happen, especially in England."