REUTERS: Chelsea's Kai Havertz said he is now free of injury and illness and there can be no excuses if he fails to deliver at Stamford Bridge.
The German midfielder managed just one goal and four assists in 21 league appearances since arriving from Bayer Leverkusen for 71 million pounds (US$98.20 million).
Havertz, 21, was laid low by COVID-19 in November and was then used mostly as a substitute before picking up an injury last month.
"The coronavirus is now over (for me) and I feel good," Havertz told Chelsea's website. "I had a little injury in the past few weeks but it's now time to play good.
"It has not been easy for me but there are no excuses.
"I just have to keep on working and hopefully there will be a big turnaround soon."
Chelsea host Atletico Madrid in the second leg of their Champions League last-16 tie on Wednesday. They won the first leg against La Liga side 1-0 in Bucharest.
(US$1 = 0.7230 pounds)
(Reporting by Arvind Sriram in Bengaluru; Editing by Peter Rutherford)