OAKLAND, Calif. -- Orioles left-hander Arthur Rhodes tested his tendinitis-ridden left knee in the bullpen yesterday and came out of the shortened session expecting to be placed on the 15-day disabled list.

"I'll probably go on the DL and make my next start the 21st," said Rhodes, who had arthroscopic surgery on the knee last season. "I was starting to throw the ball real good, but when things happen things happen."

Rhodes hurt the knee in Sunday's game against the Seattle Mariners, leaving in the fourth inning. In his previous start, he had pitched a complete-game three-hitter against Oakland.

The Orioles delayed a roster move on Rhodes until today or tomorrow. The timing of the injury is fortunate for the Orioles, who after Saturday will not need their fifth starter again until May 21.

Right-hander Mike Oquist, who has made six major-league relief appearances, has been scheduled for his first major-league start Saturday against the Cleveland Indians.

Orioles manager Johnny Oates did not say whether he would keep 11 pitchers or trim to 10 with the four-man rotation. If he goes with 10 pitchers, outfielder Damon Buford would be a candidate for promotion.