MILWAUKEE, SEPT. 2 -- The charitable-of-late Baltimore Orioles righted another opposing pitcher and continued their slide toward the nether regions of the American League East today, prompting their mild-mannered general manager to offer a stern warning about future job security.

Milwaukee Brewers right-hander Jaime Navarro (6-5) limited the Orioles to eight hits and two runs over 8 1/3 innings to lead a 4-2 victory before 18,396 at County Stadium. It was the Orioles' third straight defeat; they have lost eight of nine and 19 of 26 contests since they last were at the .500 mark.

The Orioles left tonight for Baltimore -- where they'll play 15 of their next 19 games -- with a 60-72 record and a 15 1/2-game deficit in the AL East. The Orioles scored six runs in this three-game series and lost with a variety of bizarre scripts; the one constant, as it has been for the past month, was a lack of timely hitting.

The fragile fabric that holds a ballclub together mentally is being severely tested. "It's hard not to doubt yourself at this point," catcher-first baseman Mickey Tettleton said. "Over the course of a season, you're going to have your ups and downs. But we've devoted a lot of time to our downs."

The downward slide prompted a postgame word of caution from General Manager Roland Hemond. The Orioles apparently remain committed to their young players and a long-term plan of having a legitimate contender in place by 1992, but Hemond said today that a September evaluation period could force changes in the blueprint.

"I'm not questioning their effort, but they have to show they can win ballgames if they want to remain part of this program," he said. "It's a constant process. You always try to evaluate and re-evaluate.

"We'll evaluate September on how players react to the situation. People have to come to the forefront. Everyone's always being tested. We won't just gracefully accept defeat. . . . If the solutions don't take place from within the ranks, then we'll have to look for other solutions.

"The building process is not carte blanche assurance {to the team's young players} that they have jobs."

Hemond is not one to tip his hand publicly or stage hair-raising tantrums, so today's comments represent about the most forceful kick in the pants he can offer. He said he hasn't yet seen reason to alter the Orioles' plan, but that view could change.

"We can be very competitive" with this collection of players, Hemond said. "You don't deviate from your plan, you try to supplement what you have. . . . You recognize slumps also. I still have faith in the guys who are here. You don't write off players because of a short stretch. . . . A lot of it is still the growing process" of the young players.

If evaluations were to be made hastily, these Orioles certainly would be discarded. The latest beneficiary of their generosity was Navarro, a second-year player who had a 5.06 ERA in his previous seven games. He began his resurgence with a pair of complete-game efforts to close out August, but even those impressive performances lacked the dominance he exhibited today.

Navarro (6-5) held Baltimore scoreless for eight innings. His bid for his first career shutout was broken in the ninth on Craig Worthington's one-out single and Mike Devereaux's two-run homer, the center fielder's third hit of the game.

"I wanted the shutout very bad," Navarro said. "I'm mad at myself I didn't get it." It mattered little, however, for the Brewers had a 4-0 cushion by then. Reliever Chuck Crim earned his ninth save by getting two outs.

Milwaukee (63-69), which has achieved three series sweeps this season, has won 10 of its last 13 games.

"You know what I said yesterday? Just change the names and it still applies," Orioles Manager Frank Robinson said. "It's been the same for us for the last month.

"They didn't crush the ball, either. They got key hits at the right time. I'd love to get 20 hits a game, but it's not going to happen. We're not getting hits at the right time. You can't will people to hit. You just have to wait for them to perform."

Baltimore's Jose Mesa had a credible outing in his second start since being recalled from Class AAA Rochester. The 24-year-old right-hander yielded five hits, four walks and three runs over six innings, struggling to control his fastball but usually compensating with a curveball and change-up that proved surprisingly deceptive.

"I felt more comfortable and more relaxed," he said. But "I was behind in the count every time and that makes it hard."

Mesa (0-2) allowed a run in the second when, with the bases loaded and two outs, he threw an 0-2 curveball to Bill Spiers into the dirt and past Tettleton. He escaped further damage by striking out Spiers on the next pitch, but surrendered another run in the fourth on singles by Dave Parker and B.J. Surhoff, a sacrifice bunt by Greg Vaughn and Greg Brock's sacrifice fly.

The Brewers made it 3-0 in the fifth when Mesa hit Jim Gantner with a pitch and gave up singles to Parker and Surhoff. Brock's solo homer off reliever Jeff Ballard in the eighth pushed the advantage to 4-0, and the Orioles offered little resistance until the ninth.

"We just keep coming up short, and it's one thing after another," Worthington said. "We'd better do something, or else we're going to be 30 games out before it's over."