Sterling went down after a collision with Ilkay Gundogan in the first minute of tonight’s match at Stamford Bridge.
After briefly testing his leg out with the medical staff on the touchline, he asked to come off and Pierre-Emerick Aubameyang took his place after only five minutes.
The game was not even 20 minutes old when Pulisic was injured by John Stones’ sturdy, goal-saving challenge. After treatment, it was decided he could not continue and Carney Chukwuemeka was introduced.
The blows came after Mason Mount had pulled out of the match ahead of kick-off.
The midfielder suffered a knock in training to extend Graham Potter's injury crisis to ten players.
The Blues hope to welcome back Ruben Loftus-Cheek, Edouard Mendy and Ben Chilwell in the coming weeks.
But, in the long-term, they are without N'Golo Kante, Wesley Fofana, Armando Broja and N'Golo Kante.
Chelsea hope to bolster their squad with the signing of Mykhaylo Mudryk in January having already landed Benoit Badiashile and David Datro Fofana, although Potter does not want to introduce the young forward to first-team action yet.