Hart played on after suffering a cut close to the eye to make a number of crucial saves as City claimed a hard-fought 1-0 win at the Etihad Stadium.
A club official later confirmed Hart had needed five stitches after being hurt in a collision with Palace striker Cameron Jerome during the first half.
His man-of-the-match performance in the second half, as Palace grew in confidence, made light of the injury and fully justified his recent recall to the side after being dropped for a spell.
Manuel Pellegrini: "It was not a serious problem. The doctors said he doesn't have serious problem. There isn't a problem with his sight.
"I repeat what I said last week, it was very good for Joe Hart to have a rest.
"He needed a rest and he is playing at his normal performance level, as the good goalkeeper he is.
"He worked very hard but he was always confident he would return to his position."