BALTIMORE, JUNE 12 -- Just when the Baltimore Orioles appeared on the verge of recalling 1989 No. 1 pick Ben McDonald from Class AAA Rochester, he has developed a second severe blister on his right index finger.

This one is on the tip of the finger and comes when a similar one on the side of the finger has healed. It's serious enough that McDonald has been scratched from his scheduled start at Des Moines Wednesday night and probably will be brought back to Baltimore to be examined by team doctors.

This latest blister developed last Friday and is one more setback in a rookie season that already has been long on frustration. McDonald, the heralded No. 1 pick in last summer's draft, was the Orioles' best pitcher in spring training and had locked up a spot in the rotation when he pulled a muscle in his side during his last start.

That forced him onto the disabled list and McDonald still hasn't returned to the big leagues. This injury is particularly frustrating for the Orioles and McDonald because they appeared to be about ready to recall him to take the place of slumping Jay Tibbs in the rotation.

"I feel so sorry for him," General Manager Roland Hemond said. "He has looked so good when he's healthy, but he just hasn't been able to shake these little nagging things."

Hemond said McDonald would be brought back to Baltimore to get the blister problem "cleared up once and for all. The layoff after the injury really hurt him. You toughen your hands during spring training, and by the time he was able to pitch again, he'd lost some of that toughness."

With McDonald unable to pitch for at least another week, Manager Frank Robinson remained noncommittal about what he'll do with Tibbs's spot in the rotation. Jose Bautista appears to be a possibility, but Tibbs might be given another chance. If someone is recalled from Rochester, it probably would be John Mitchell, who is 5-0 since being sent down when the rosters were reduced from 27 to 25.

Frederick's Gain

The Orioles announced they've moved their Florida Instructional League team from Sarasota, Fla., to Frederick, Md., and that it will play 36 games against area colleges, including Maryland, George Mason and George Washington.

The instructional league is an annual postseason program for about 33 first-year pro players and selected older players who need to work on a particular problem. Teams traditionally headquarter in Florida and play a schedule similar to that of spring training.

But the Orioles say they decided the weather in Maryland is good enough in September and October to allow for the switch. Orioles executive Ken Nigro came up with the idea, and the more the Orioles studied it, the more they liked it.

Players will not only play games in the area, but be tutored by Orioles coaches, use the weightlifting equipment at Memorial Stadium and attend public appearances with older Orioles.

The team will play 31 of its 36 games at the new Harry M. Grove Stadium in Frederick. The schedule begins with a doubleheader at Liberty University on Sept. 8 and ends with one against James Madison on Oct. 7. Six local schools also will host games.

"I played six seasons in the Yankees and Pirates system and never met the general manager," Orioles farm director Doug Melvin said. "We don't want that to happen with the Orioles. With this kind of program, we'll be able to present ourselves to the players. It's an experiment, but I feel so good, I think other clubs will try it too."

George Mason Coach Bill Brown said he too liked the idea: "Some of our players will go on and have pro careers and they'll have the chance to see what it takes to play at that level. I really think it'll help us turn our program up a notch."

Doing the Shuffle

The Orioles activated infielder Tim Hulett and placed infielder Marty Brown on waivers. Brown may end up in Rochester, but first he must clear waivers, then be offered to the Cincinnati Reds.

Indications are that he'll clear waivers and the Reds aren't interested in having him back.

Hulett broke the hamate bone in his left hand at the end of spring training. He had surgery, then went to Rochester to play himself into shape. "It has been frustrating," he said. " . . . It was hard to watch and be patient. It's good to be back."