Roone Arledge has shaken up his ABC lineup and will open with Keith Jackson as the surprise leadoff man and Howard Cosell in the cleanup spot on the Monday night baseball telecasts.

Moving in a heavy hitter such as - Cosell was a message to baseball commissioner Bowie Kuhn that nobody in the sport is big enough to tell Arledge who he can put at a microphone. Kuhn was averse to Cosell because of disparaging remarks the announcer has made about baseball.

Bob Uecker, "the expert analyst" and aspiring comic, is the only member back from the team that started the 1976 season.

Bob Prince, the play-by-play man, left the booth before the end of last year and "host" Warner Wolf is newly cast as one of the current three play-by-players, behind Jackson and Al Michaels.

On the second team with Michaels last season were Bob Gibson and Norm Cash, but Cash was dropped and Bill White, the former New York Yankee, has replaced Cash. Like Uecker, former players Gibson and White are "experts."

There had been speculation that Michaels would be the first-team play-by-play man this season and that Wolf might not be assigned to baseball again.

Cosell will do "a limited number" of games, as his other commitments permit. He worked the American League playoff game in 1976. HKE WAS ASKED YESTERDAY TO COMMENT ON A MEETING BEFORE THOSE PLAYOFFS WITH Kuhn and Arledge at the renowed "21" restaurant in New York city.

"When Roone assigned me," cosell said on the telephone from ampa, Fla., "I told him he better be prepared for all kinds of flak because of my past criticisms of baseball. My thinking is that a reporter who covers a war doesn't have to love war.

"I said there would be enormous flak from Bowie, but Roone asked me if I would have lunch with him and Kuhn.

"I made it clear I didn't ask for the baseball assignment: that Roone did. I told Bowie, 'I'm a lawyer and you're a lawyer. You're not an indecent man, but I can't be . . . I won't be . . . your flack.'

"I went before Congress on five occasions, and you know I personally objected to baseball's exempton from the antitrust laws; the carpetbagging of franchises around the country, and the ugly Washington situation (of not having a franchise), making it hypocritical to call baseball the "national" sport.