BALTIMORE, AUG. 24 -- The Baltimore Orioles likely will depart from their four-man pitching rotation early next week, but it's unclear who will become the fifth starter.

A day off each of the past two weeks has allowed Manager Frank Robinson to stay with the four-man rotation while usually allowing the starters four days rest between outings. But the Orioles today began a stretch that will see them play each of the next 13 (and 26 of the next 27) days, and Robinson is wary about overworking his young staff.

He'll be particularly careful with tonight's starter, Anthony Telford, who still is rehabilitating a shoulder injury that caused him to miss 15 months after undergoing surgery in August 1988. Telford was on a loosely enforced pitch limit while in the minor leagues this season, and Robinson said: "My gut feeling is that I will not let Telford pitch on three days rest."

If not, Baltimore would need a starter Tuesday against the New York Yankees. The prime candidate would seem to be Bob Milacki, who's eligible to be activated from the disabled list and has his strained right shoulder nearing full strength.

Milacki threw for a pain-free 20 minutes in the bullpen today, including the equivalent of an inning at full tilt. But pitching coach Al Jackson said he'd like to have Milacki pitch to hitters in a simulated game Monday, and that he probably won't be ready for game action until late next week. Bad News on Injury Front

Aside from Milacki, the Orioles' injury news was discouraging today. Reliever Mark Williamson said he now is looking at a four- to six-week recovery period for his fractured ring finger, meaning he most likely is through for the season. He is scheduled to have more X-rays performed Tuesday, with surgery still a possibility.

First baseman Randy Milligan said he still is unable to swing a bat with his slightly separated left shoulder. He likely won't return to full-time duty until mid-September. And pitcher Dave Johnson's strained lower back hasn't improved significantly in the past week, leaving him doubtful he'll be ready to start when he's eligible to come off the DL Aug. 31.

Even rookie pitcher Ben McDonald is ailing a bit, reporting today he was plagued by his months-old blister problem and back spasms during his loss Wednesday in Boston. He said he doesn't think either injury is serious. Concern Over Juan Bell

The Orioles' braintrust apparently is concerned about the attitude problems of one of the organization's brightest prospects, shortstop Juan Bell. The latest in a series of episodes occurred Wednesday in Syracuse, N.Y., when Bell -- acquired in the Eddie Murray trade -- and teammate Donnell Nixon fought on the bench of the Class AAA Rochester Red Wings, even as the club was en route to a division title-clinching win.

Today's accounts held that the scuffle was rooted in a pregame confrontation the two had on the team bus, but fisticuffs came about only when Bell -- who hasn't played for six weeks because of a nerve injury in his leg -- walked by Nixon in the dugout and performed an offensive act.

"All we've heard all year is how much better {Bell} has gotten attitude-wise and how he's gotten along with his teammates," an Orioles official said. "But things like this make you wonder." . . .

Shortstop Cal Ripken turned 30 today, making him the fifth player on the team's roster to reach that age. The club's nine-man pitching staff averages 25 years 8 months -- second youngest in the majors (to the Chicago White Sox). . . .

Baltimore announced today it has signed its 14th-round pick from June's amateur draft: 6-foot-4, 210-pound outfielder Scott Miley of Fremont, Calif. The team has signed 12 of its top 14 selections and 30 of 45 overall.