Ascanio, who has been sidelined since undergoing right shoulder surgery in October 2009, was struck on the right side of his head by a line drive in Indianapolis' game against Toledo on Thursday night. The right-hander was starting the second game of Indianapolis' doubleheader.
Ascanio walked off the field on his own after the incident and was taken to a local hospital for additional tests. Doctors diagnosed him with a facial contusion.
The Pirates released a statement saying that Ascanio's status is uncertain at the time. The team did not estimate how long Ascanio might be sidelined.