Andrew McCutchen diagnosed with rib cartilage injury

Pirates outfielder Andrew McCutchen has been diagnosed with "an avulsion fracture involving the costochondral cartilage of the left 11th rib," the team

Pirates outfielder Andrew McCutchen has been diagnosed with "an avulsion fracture involving the costochondral cartilage of the left 11th rib," the team announced Tuesday. He will remain on the active roster. 

In simpler terms, McCutchen's injury is a separation between the rib bone and cartilage. It is not a fracture of the bone. He is currently considered day-to-day. It was previously reported that he could miss three or four weeks. 

More: Pirates' playoff hopes take a big hit after Andrew McCutchen's injury​

On the first through tenth ribs, the costochondral cartilage connects the the rib to the sternum. On the 11th and 12th ribs, however, the cartilage is just a small end cap. McCutchen's injury is in the 11th rib on his left side. 

FOXSports.com's Ken Rosenthal spoke with an unnamed MLB trainer who said the injury is worse on the left side because it affects the righthanded McCutchen's ability to hit and throw. The trainer also said it is unlikely the injury resulted from McCutchen's being hit by a pitch Saturday. Pirates manager Clint Hurdle echoed that sentiment.

McCutchen, the 2013 NL MVP, was named to his fourth consecutive All-Star team this season. He is batting .311 with a .536 slugging percentage.

The Pirates are 1.5 games behind the Brewers in the NL Central, and a half game back of the final Wild Card spot. 

More: MLB Power Rankings: Pirates keep rising as playoff push continues​

- Dan Gartland