Houston's Chris Johnson hit a sharp ground ball down the third-base line in the seventh inning. Ramirez dove to his right, and the ball popped up and hit him in the face. After briefly laying on the ground, Ramirez was helped off the field.
The Cubs said Ramirez suffered a lip laceration and will need a few stitches but he did not lose consciousness.
Rookie DJ LeMahieu replaced Ramirez at third.
Ramirez isn't the only Cub to take a ball to the face recently. Teammate Marlon Byrd was beaned on May 21 and said Wednesday that he hopes to be back by July.
The Cubs have six players from the Opening Day roster on the disabled list. Leftfielder Alfonso Soriano, who has a left quad strain, was the latest addition on Tuesday.
Ramirez is batting .289 with two home runs and 19 RBIs.