Heaverlo was examined by Mariners medical director Dr. Larry Pedegana and is scheduled to undergo an MRI to determine the extent of the damage.

"If he requires surgery, Jeff could miss all of 2002, but I would expect that he would be ready for spring training next season," Pedegana said.

The 24-year-old Heaverlo was named Most Valuable Pitcher for Class AA San Antonio of the Texas League last season after going 11-6 with a 2.12 ERA in 27 starts. He was selected in the supplemental first round of the 1999 June draft after setting the career strikeouts record at the University of Washington.

"We're obviously disppointed, but mostly for Jeff," Mariners general manager Pat Gillick said. "He worked very hard this winter so he could come to camp and compete for a job and he was in great shape. The good news is he's still a very young pitcher and, while this is a setback, we expect him to have a fine career with the Mariners."