Dave Stewart pitched a four-hitter and Rickey Henderson had a two-run double as the Athletics beat the Royals, 5-0, yesterday in Oakland, Calif., to send Kansas City to its fifth straight loss.

Meanwhile in San Francisco, Oakland outfielder Jose Canseco, complaining of lower back pain, checked into Children's Hospital for tests and observation of a sciatic nerve condition.

It was Stewart's first shutout of the season and fifth of his career. His last shutout came Aug. 30, 1988, when he beat Boston and Roger Clemens.

Stewart (9-3) struck out eight, walked two and joined Clemens (10-2) as the only nine-game winners in the American League this season. Both of Clemens's losses were to Stewart.

The Royals have scored a total of four runs in their last four games.

"If anybody can explain our lack of hitting, they're better than me," Kansas City Manager John Wathan said. "It's hard to tell whether it's our hitting or their pitching. It's probably a combination of both -- a bad combination."

Felix Jose's infield single with one out started the A's fourth inning off starter Kevin Appier (1-2). Walt Weiss walked and after Mike Gallego flied out to right, Henderson scored both runners with a double over the outstretched arm of center fielder Bo Jackson.

Team physician Allan Pont said Canseco had a C.T. scan of his spine, which is a computerized view of lower back and discs. He will remain in the hospital "for a couple of days," Pont said.

"We got him off his feet," Pont said. "It should help him get rid of the muscle spasms. The clinical condition is most important to us."

Pending further test results, Canseco, who has missed two straight games against the Royals, is expected to rejoin the team Monday. Pont did not say when he expects test results.

Red Sox 11, Indians 5: As Boston's manager, John McNamara loved Ellis Burks. Now, as manager of the Cleveland Indians, McNamara has the utmost respect for Boston's center fielder.

Burks continued to feast on Cleveland pitching, driving in six runs with a homer, double and single in Boston as the first-place Red Sox collected their seventh consecutive victory.

"Tell me about him, he's a good player and when he gets hot he can hurt you," McNamara said. "But our biggest headache was the base on balls. We walked eight and six of them scored."

Burks had a two-run single with the bases loaded in the first. Then, after a solo homer in the sixth, he hit a three-run double high off the wall near the 379-foot mark in right-center in the eighth.

In his four years with the Red Sox, Burks is 19 for 51, a .373 average, with five grand slams when batting with the bases loaded. He is three for seven with seven RBI this season.

Angels 8, Rangers 3: Rick Schu hit a two-run homer and Wally Joyner added a two-run single in a five-run fourth inning, boosting Kirk McCaskill to his 60th career win in Anaheim, Calif.

McCaskill (4-3) lasted long enough to improve to 60-47 lifetime and move into sole possession of sixth place on California's all-time win list. McCaskill allowed five hits, struck out three and walked one in 5 1/3 innings. He left after losing his shutout, complaining of stiffness in his right elbow.

The Angels, who also got leadoff homers from Brian Downing in the first and Dick Schofield in the seventh, climbed one game above .500 for the first time since April 18, when they were 5-4.

Mariners 5, Tigers 2: In Detroit, rookie Russ Swan pitched seven no-hit innings and allowed two hits over eight innings for his first major league victory.

Swan, acquired from the San Francisco Giants on May 24, lost his no-hit bid when Cecil Fielder led off the eighth inning with a line-drive single to left.

Tracy Jones followed with a single but Lloyd Moseby grounded into a double play and Ed Romero flied to right. Mike Schooler pitched the ninth, allowing a two-run homer to Tony Phillips.

Swan struck out only one hitter, Phillips in the first inning, and did not issue a walk.

Swan (1-0) was trying to become the second Seattle pitcher in a week to no-hit the Tigers. Randy Johnson pitched the first no-hitter in Mariners' history last Saturday, beating Detroit, 2-0, at the Kingdome.

Blue Jays 7, Brewers 3: In Milwaukee, Dave Stieb allowed seven hits in eight innings for his seventh straight victory.

Milwaukee's 13th loss in 17 games dropped the Brewers under .500 for the first time since April 18.

Stieb (8-2) hasn't lost to the Brewers since September 1987 and has allowed only five earned runs in his last 55 innings against Milwaukee. He gave up three runs, two earned, walked one and struck out three before Tom Henke finished up.

White Sox 4, Twins 2: Eric King and two relievers combined on a seven-hitter in Minneapolis and Carlton Fisk hit his 340th career home run.

King (5-1) allowed six hits, struck out three and walked none before giving way to Jones with one out in the seventh. Jones allowed one hit in 1 1/3 innings and Bobby Thigpen pitched the ninth for his 19th save in 22 opportunities.

Fisk led off the second inning with his fourth homer of the season, a solo shot off Allan Anderson (2-8) that gave the White Sox a 1-0 lead. The homer moved Fisk past Boog Powell for 45th place on the all-time list.

Twins second baseman Fred Manrique and Manager Tom Kelly were ejected by home plate umpire Jim Joyce in the fifth inning. With one out, Junior Ortiz singled and went to third on a single by Dan Gladden. Manrique fell behind 0-1 and when Joyce called the next pitch a strike, Manrique argued twice and was ejected.

Kelly bolted from the Twins' dugout and was immediately tossed out by Joyce.