Lerew bruised his right ribs and right biceps after being struck by an Edwin Encarnacion line drive in the second inning of the 13-1 defeat.
"To be quite honest with you, I don't see it happening," Royals manager Ned Yost said Wednesday of Lerew making his scheduled start at Yankee Stadium on Sunday. "He's pretty sore. We'll just have to wait and see."
Yost said outfielder Rick Ankiel would likely be recalled from his minor-league injury rehab assignment with Triple-A Omaha and join the club Thursday for the first game of the series at New York.
"My thinking right now is Ankiel is due to come back here very soon," Yost said. "If we have to DL [Lerew], then we'll put Ankiel in his spot and then on Sunday we'll have to make a decision and make a roster move to bring up another pitcher."
Ankiel hit .210 in 19 games before going on the disabled list May 3 with a pulled right quadriceps.
Lerew is 1-4 with an 8.54 ERA and allowed nine home runs in 26 1/3 innings in six starts after a June 16 promotion from Omaha.