MINNEAPOLIS, JULY 4 -- The body that is the Baltimore Orioles grew a little colder tonight as rookie Les Straker allowed four hits over seven innings and Kent Hrbek hit his 21st homer to lead the Minnesota Twins to a 4-1 victory before 23,724 at the Metrodome.

Les Straker? Rookie? He's 27 years old, Venezuelan, and after 10 years in such places as Eugene, Billings and Albany, is another part of the Twins' 1987 success story. In winning his fourth game, he fed the Orioles a diet of medium-speed fastballs and decent breaking pitches.

The stuff may not have been overpowering, but the results were. The Orioles (31-49) got only one run off him, and he was at his best with men on base, leaving runners on second and third in the third inning and on third base in the sixth.

He handed the Orioles their sixth loss in succession, 29th in 34 games and beat rookie Eric Bell, who dropped to 6-6 and hasn't won since May 25. Bell needed 102 pitches to get through 6 2/3 innings and was charged with four earned runs, two of them when Hrbek's homer broke a 1-1 tie in the third.

The only fireworks from the Orioles this night came from Manager Cal Ripken Sr., who was thrown out in the sixth inning for arguing a strike call on Cal Ripken Jr. by plate umpire Tim Tschida. It was Ripken's third ejection of the year. He stayed on the field, carrying on, for about 10 minutes, finally having to be led to the dugout by umpire Steve Palermo. Ripken Jr., who protested initially, wasn't raucous enough to incur the end of his record streak of consecutive innings played.

"Oh, I didn't think I got that mad," Ripken Sr. said, playing down the incident. "Really, I thought he umpired a pretty good game."

Tschida almost saluted Ripken, saying, "I let him have his say, and he aired it out pretty good."

The day had a familiar beginning for the Orioles, with General Manager Hank Peters calling the players into the clubhouse, closing the door and talking about the team's long, dismal slump and the performance of certain players.

Peters was talking to his team at a time when more than the pitching has gone bad. The Orioles entered tonight still leading the league in homers, but by only two over Detroit, 113 to 111. But in just about every other category, they've slipped badly, having dropped to 10th in runs and batting average and ninth in walks. Larry Sheets leads them with a .315 batting average and Ripken Jr. is hitting .276, but no one else is above .270.

"It wasn't a chewing-out session or an inspirational talk," Peters said. "I told 'em some things I thought they needed to hear from me."

Peters again emphasized that changes were coming, another indication the Orioles are beginning to look to 1988. He said there would be more younger players in the lineup and hinted that second baseman Bill Ripken could be called up from Class AAA Rochester.

One of the changes occurred tonight when Ripken Sr. announced that rookie Mark Williamson had been moved back to the bullpen and replaced in the rotation by rookie John Habyan. One reason is that the Orioles want to see Habyan, Bell and, eventually, Ken Dixon and/or Jeff Ballard in the rotation for the second half of the season. But Ripken also said, "Mark is more valuable to us in the bullpen. We need someone more reliable out there."

Williamson, who pitched 1 1/3 innings in relief of Bell tonight, said the move was fine with him, adding, "I like coming to the park thinking I might get in the game. When I was in the rotation, I didn't like those days off. I'd get edgy to be out there, and I'm used to pitching a lot."

But after the meeting and the talk of changes, the Orioles played a game that looked like a lot of others. They found themselves behind early, got back in the game, then had a pitcher give up a big home run.

In the first, the Twins got a 1-0 lead when Dan Gladden doubled, stole third and scored on a wild pitch by Bell. The Orioles tied on Lacy's broken-bat single in the third, but in the home third, Kirby Puckett singled and Hrbek's home run made it 3-1.

It went to 4-1 in the seventh when Greg Gagne singled, moved up on an infield out and scored on Puckett's third single. The hit raised Puckett's average to .354.

After Straker shut the Orioles down for seven, Twins Manager Tom Kelly turned the game over to Juan Berenguer, who went the final two innings for his third save.

Orioles Notes:

Pitching coach Mark Wiley will watch Dixon pitch in Rochester. Dixon has won back-to-back starts since being demoted, but Peters said, "He went down there to make some adjustments, and hasn't made them yet."