Kansas City won the first game 2-1 as Danny Duffy took a no-hitter into the sixth inning and pitched a combined two-hitter.
Royals pitching held the Tigers to a run and six hits for the two games.
Eric Hosmer homered in each game.
Shields (8-8) won his fourth game in his past five starts. He walked four and struck out one.
Luke Hochevar pitched a perfect eighth and Greg Holland worked the ninth, allowing a hit, for his 34th save. He had saves in both games of the doubleheader.
Jose Alvarez (1-3), called up from Triple-A Toledo to make the start, took the loss. He gave up two runs and five hits in 5 2/3 innings, walking three and striking out five.
Alvarez's only big mistakes came in the third with two outs. He walked Jamey Carroll and Hosmer followed with his second home run of the day, that gave the Royals a 2-0 lead. Hosmer blasted Alvarez's 1-1 pitch deep into the right-field stands for his 14th homer.
Duffy (1-0) beat Justin Verlander in the opener.
Duffy was called up from Triple-A Omaha to make his second big league start of the season, and didn't allow a hit until Cabrera's hard-hit, two out single in the sixth.
RAYS 5, BLUE JAYS 4
ST. PETERSBURG, Fla. (AP) — Jose Lobaton hit a game-ending triple with one out in the ninth inning, lifting Tampa Bay to its third straight victory.
Lobaton's triple came off Aaron Loup (4-6) Yunel Escobar walked. Lobaton had three hits.
Fernando Rodney (5-3) gave up two hits to start the ninth, but worked out of the jam.
The Blue Jays had tied it in the eighth when, with runners on second and third and one out, Anthony Gose hit a grounder to shortstop. Escobar threw offline to home plate and Brett Lawrie scored.
In his fifth start this season against Tampa Bay, R.A. Dickey gave up six hits and four runs over seven innings.
YANKEES 10, RED SOX 3
BOSTON (AP) — Alfonso Soriano drove in four more runs and Andy Pettitte avoided his first-inning troubles to lead New York over AL East-leading Boston.
The Yankees won for the fifth time in six games and sent the Red Sox to their third consecutive loss. With Tampa Bay's victory over Toronto, Boston's lead in the division was trimmed to one game.
Soriano was 3 for 4 with a hit-by-pitch and a three-run homer in the third that made it 6-0. He has 13 hits and 18 RBIs in his last four games.
Alex Rodriguez had a pair of singles while getting booed loudly in his first appearance in Boston since he was suspended 211 games in baseball's latest steroid scandal. Rodriguez, who is allowed to play pending his appeal, was also mocked by fans with chants of "You do steroids" and signs that said, "A-Roid" and "AFraud."
ATHLETICS 3, INDIANS 2
OAKLAND, Calif. (AP) — Yoenis Cespedes hit a two-run homer in the first, Eric Sogard put Oakland ahead on a seventh-inning double and the Athletics beat Cleveland.
Former A's fan favourite Nick Swisher tied the game at 2 in the seventh with an RBI single, and winner Sean Doolittle (4-4) walked the bases loaded before getting out of it with only the one run. Swisher, booed at every chance, grounded out with runners on first and second to end the eighth.
Grant Balfour pitched the ninth for his 31st save in 32 chances, allowing a one-out walk to Carlos Santana and Michael Brantley's single before Asdrubal Cabrera lined into a game-ending double play as the A's held on to win for the first time in five tries this year against the Indians.
Cleveland All-Star Justin Masterson (13-9) lost consecutive decisions for just the second time this season. He allowed three runs on seven hits in 7 2-3 innings after coming off his shortest outing of the year, 4 1-3 innings in which he allowed five runs and seven hits against the Angels.
MARINERS 3, RANGERS 1
ARLINGTON, Texas (AP) — Kyle Seager snapped a career-worst 0-for-21 slump with a go-ahead two-run homer and Seattle beat Texas.
Hisashi Iwakuma (11-6) struck out eight and allowed one run in seven innings.
Derek Holland pitched two-hit ball with six strikeouts over seven scoreless innings for Texas before Neal Cotts (4-2), whose 0.93 ERA was the lowest among American League relievers, walked Franklin. Seager then lined a shot into the Rangers bullpen in right-centre field, his 18th homer of the season but first in 13 games.
Justin Smoak homered in the ninth for Seattle, which won for only the seventh time in 19 games.
WHITE SOX 5, TWINS 2
MINNEAPOLIS (AP) — Adam Dunn hit his 28th home run and Jose Quintana threw six sharp innings to lead Chicago over Minnesota.
Quintana (7-4) allowed six hits in 6 2-3 innings, giving up two runs and striking out seven.
Jeff Keppinger also homered to help Chicago snap its season-worst, 10-game road losing streak.
Joe Mauer homered in the first for Minnesota, but Keppinger and Dunn both hit solo shots off Twins starter Kevin Correia (8-9) in the third to make it 4-1. Quintana breezed through Minnesota's lineup the rest of the way after losing his previous start against the Twins on Sunday in Chicago.
ASTROS 8, ANGELS 2
ANAHEIM, Calif. (AP) — Chris Carter hit a three-run homer and drove in a career-high five runs, and Brad Peacock didn't allow an earned run while pitching into the seventh inning of Houston's victory over Los Angeles.
Robbie Grossman drove in a run and scored during a three-run fifth for the major league-worst Astros (40-81), who have won three of four for the first time since June 18.
Peacock (2-4) earned his first victory since April 10 after two hard-luck losses following his return to the rotation. The rookie yielded four hits and two unearned runs, striking out five.
Hank Conger drove in a run during his first multihit game since June 30 for the foundering Angels. They've lost 15 of 21, including five straight at home.
ROCKIES 6, ORIOLES 3
BALTIMORE (AP) — Colorado hit four home runs, including a tiebreaking, two-run shot by Wilin Rosario in the seventh inning, and the Rockies beat the Orioles to extend Baltimore's losing streak to four games.
Charlie Culberson, Charlie Blackmon and Todd Helton also homered for the Rockies, who have won six of seven. It was Culberson's first major league home run in 55 at-bats.
Juan Nicasio (7-6) allowed two runs, four hits and four walks over six innings to earn his first win in five starts since July 20. The right-hander yielded 15 runs over 14 innings in his previous three outings and was 0-3 with a 7.79 ERA in four interleague starts this season.
Wei-Yin Chen (6-6) retired 12 of his first 13 batters but couldn't get out of the seventh inning. He gave up four runs and five hits in 6 1-3 innings in losing his third straight start.
Nate McLouth and Matt Wieters homered for the Orioles, who were coming off three straight one-run defeats in Arizona.