Mike Flanagan, who doctors say will be on the disabled list for two months with a knee injury, has issued a challenge to Jim Palmer, who now is eligible to come off the DL.

"I told Jimmy that I'll beat him back," said Flanagan today.

While many a Baltimore Oriole had a long face after hearing the prognosis that Flanagan will be out for eight to 10 weeks with an "incomplete tear of the medial collateral ligament," Flanagan no longer is one of the downcast.

"Oh, I don't feel bad at all, not anymore," said Flanagan, the Orioles' durable Iron Mike who had the fastest start of any pitcher in the majors (6-0) before he was hurt in a freak accident, lunging for a ground ball on Tuesday. "After the first specialist saw me, right after it happened, I was pretty much resigned to missing the whole season. They told me I had just what Timmy (Stoddard) had last season and I knew everything he'd had to go through to come back.

"I was really down," Flanagan said in a telephone interview yesterday.

"But since they told me that the ligament wasn't torn or pulled away from the bone and that I wouldn't have to have surgery, I've felt much better . . . They say I should be back sometime in July. I'm looking forward to getting 15 more starts this season. Maybe I can still go undefeated . . .

"I told Palmer if he doesn't hurry, I'll beat him back."

Flanagan went to Union Memorial Hospital on Wednesday expecting to learn that he would have to have major knee surgery, followed by months of rehabilitation with no guarantee that he would ever return to full strength.

"I kept waiting for them to say, 'It's completely torn.' But they never did. They drained the fluid out of the knee and it was only 10 ccs, which is nothing. There was minimal blood. They pumped air into it and took a moving X-ray, where they move your knee in every direction, and they said there was no tear at all.

"It was just a complete freak accident where I must have gotten the knee in exactly the wrong position."

Flanagan's left knee will be kept immobile in a walking brace for two weeks. Then, he will switch to a smaller brace for two weeks. After that "it will be up to me," he says. "I can start light running and light throwing and rehabilitation exercises for the knee.

"I'm not going to run back out there too soon. They'll measure the strength of the knee every day on a Cybex machine to find out when it's as strong as the good knee.

"You know, those are the three stages of a pitcher's career--Cy Young, Cy Old and Cybex," said Flanagan, clearly back to his old self.

The return of Flanagan's trademark humor should be the best sign to his teammates, who were upset by Flanagan's hard-jawed silence after he screamed, rolled in the grass near the mound, then limped off the Memorial Stadium mound.

"It never happens when you're 0-4," quipped Flanagan yesterday. "Then, you try to get hurt."

Until the news that he wouldn't have to have surgery, Flanagan had steeled himself against what he thought "would just be another test. And Kathy and I have been through a few."

Kathy Flanagan had two miscarriages before she and her husband became the natural parents last July of one of the first "in vitro fertilization" babies born in America by normal delivery.

"There's never a dull moment in our lives," said Kathy Flanagan yesterday. "The phone hasn't stopped ringing. But that's all right. Our daughter (Kerry Ellen, 10 months) likes to answer the phone." Flanagan himself has found an unexpected pleasure in answering that phone. "It's nice, I guess, to find out all the people who care about you."

By the sort of irony that Flanagan enjoys, his daughter's first birthday--July 9--falls almost exactly on the date when his rehabilitation is expected to end.

Flanagan, who has won more games than all but four pitchers in baseball since he joined the Orioles' rotation in 1977, has been mystified by an injury to an area of the body that had never troubled him. Flanagan, who once went 157 starts without missing a turn, has pitched through pain in almost all his extremities, but never expected a knee to go while making a routine play.

"Maybe I've put 150 percent of my effort into upper-body conditioning in the last couple of years, after my shoulder problems, and I should have paid more attention to the lower body. Who knows?"

Perhaps one anecdote from his incident illuminates Flanagan's character more clearly than any other. On Tuesday night, he left Memorial Stadium assuming his season, and all its bright promise after two years of shoulder rehabilitation, was dead. Because Kathy was out of town, he went to the home of Rich Dauer (also out with an injury) and his family for the night.

Flanagan and Dauer listened to the second game of the doubleheader on the radio as rookie Mike Boddicker, who'll have to take up some of the slack in Flanagan's absence, pitched a five-hit shutout for his first major league victory as a starting pitcher.

As Boddicker held a postvictory press conference minutes after the game, he was summoned away by a phone call from someone with an odd-sounding name--a phony monicker, as it proved, which the Orioles use as a secret password name when they don't want outsiders to know what they're up to.

The phone call of congratulation for the rookie was from Mike Flanagan.