Posted by Chelsea will have to leave one of their marquee signings out of their Champions League team this season.
In the last-16, the Blues will face Borussia Dortmund, with the first leg in Germany on February 15 and the return game at home on March 7.
Owner Todd Boehly completed a splurge this month with Enzo Fernandez becoming their eighth signing in a British record £107 million deal on deadline day.
Other newcomers include Atletico Madrid loanee Joao Felix, £88 million Mykhailo Mudryk, and £35 million Benoit Badiashile.
However, according to UEFA rules, only three new players can be registered for the knockout stages.
Chelsea must determine which three of the eight new faces Graham Potter will bring in before Thursday night.