Pittsburgh Pirates center fielder Andrew McCutchen (22) grimaces as he's hit by a pitch Saturday night in Arizona. The Bucs' center fielder is apparently headed to the disabled list with an oblique injury.

The Pirates are expected to place star center fielder Andrew McCutchen on the 15-day disabled list, complicating their chances of making it to baseball’s postseason for a second consecutive year.

McCutchen could be out at least three weeks or a month because of what appeared to be a serious oblique muscle injury, according to a source.

McCutchen was injured Sunday when he swung at a pitch and hit a sacrifice fly in the eighth inning of the Pirates’ game at Arizona. He grabbed his left side as he jogged to first base and needed help leaving the field and walking down the dugout steps.

McCutchen is in the running for a second consecutive National League Most Valuable Player award. He is hitting .311 with 17 home runs, 67 RBIs and has a .947 OPS.

Left fielder Starling Marte is the likely choice to replace McCutchen in center field. Marte could be activated today.