Chelsea boss Maurizio Sarri was delighted to bring on Eden Hazard late in their 3-0 win at Huddersfield Town.
Hazard saw out the final 15 minutes of the game.
He said, "I think Eden at this moment cannot play for 90 minutes. He has to improve and train. The best thing for him to do is play 15-20 minutes when the opponents are tired.
"We are lucky now because for three or four weeks we can work with one match a week, so we have to improve in this month, then it will be difficult, with three matches in a week, but I hope to improve the team."