Randolph told The Oregonian he woke up Monday morning and was surprised by pain on the top of his right foot. When he stood to get out of bed, the pain in the foot was so sharp, he fell to the floor. He was examined by a team doctor, who put him on crutches.
Coach Nate McMillian termed it a "mild sprain" in his right foot.
Randolph sat out of Monday's practice with a big ice bag wrapped to his foot.
"The X-rays are negative, but I think we're looking at [a magnetic resonance imaging] ," McMillan said.
Randolph could not recall anything that would have caused an injury. According to the newspaper, his availability for Wednesday's home game against Houston is up in the air.
Roy, a prized shooting guard, is returning after a 20-game absence caused by pain in his left heel.
Losing Randolph would be a big blow for the Trail Blazers, who are on a four-game winning streak. Randolph is averaging 25.4 points and 10.1 rebounds.