ANAHEIM, Calif. -- It was one of those "good news, bad news" days for the Los Angeles Angels on Wednesday.

The good news came on the field as they completed a three-game sweep of the defending World Series champion Kansas City Royals with a 4-2 win at Angel Stadium.

The bad news came when they found out they will lose closer Huston Street for an indefinite period of time because of a strained oblique muscle, the injury occurring when Street was playing catch in the outfield before the game.

The Angels lost nine of their previous 10 games against the Royals prior to the series -- six of seven during the regular season last year and all three in the American League Division Series in the 2014 playoffs.

But they flipped the script with 15 runs over the first two games, then making the most of their opportunities on Wednesday. They had just five hits in the game, but three of them were home runs that accounted for all four runs. Mike Trout hit a two-run homer, his fifth of the season, and Yunel Escobar and Andrelton Simmons each hit a solo homer.

"I think the biggest turnaround, in this series anyway, is on the offensive side," Angels manager Mike Scioscia said "The quality of at-bats has really jumped up. Guys are starting to drive the ball, we're hitting with runners in scoring position, we pressured Kansas City, at least in the first two games of the series, by putting guys out there, and that has to continue."

Escobar and Trout hit their home runs off Royals starter Chris Young, while Simmons connected off Luke Hochevar. Young (1-4) gave up three runs on three hits and two walks in 5 1/3 innings, striking out six.

"Unfortunately two home runs, but he only gave up three hits," Royals manager Ned Yost said of Young. "They didn't have a guy in scoring position all night long. Every run scored in that game was from a home run. He pitched fine."

Fernando Salas (1-1) got the win in relief of Angels starter Nick Tropeano, who pitched a serviceable 5 1/3 innings. Tropeano surrendered a two-run homer to Eric Hosmer in the first inning but nothing else.

Tropeano, who took the rotation spot of an injured Andrew Heaney one week into the season, has given up two runs or fewer in all four of his starts this season. However, he has failed to last at least six innings in any of them.

"I think today was just a battle day for me," said Tropeano, who has a 2.11 ERA but just one victory. "I don't think I had my best stuff location-wise, but I made pitches when I had to, and that's why it's a team game. They picked me up tremendously offensively and the bullpen was lights out."

While the Angels made the most of their hits, the Royals had 10 hits but didn't score after the first inning. Hosmer collected three hits, extending his hitting streak to a career-best 17 games.

"We're not swinging the bats real well right now," Yost said. "We were like 0 for 7 with runners in scoring position. We've got Mo (Mike Moustakas) swinging the bat well and Hoz (Hosmer) swinging the bat well and everybody else is kind of scuffling. It's just one of those things you've got to wait out until we get some guys hot."

Following Salas on the mound for the Angels was Jose Alvarez, who threw two scoreless innings, and Joe Smith, who shut the door in the ninth for his first save.

Smith was called upon because Street was down with the oblique injury, putting a damper on an otherwise upbeat finish to the homestead for the Angels.

"It happened on what was probably one of my lightest throws of the day," said Street, who is 5-for-5 in save opportunities this season. "It just kind of happened. We got an MRI which confirmed what we thought and we'll just take the next 72 hours to evaluate."

Street, however, acknowledged that an oblique strain usually means a trip to the disabled list.

"As far as the DL in concerned, I'll let them decide what they think is best for the team," Street said. "My guess would be that (he's doing to the DL), but they haven't told me anything so I don't want to jump the gun."

In Street's absence, Smith likely will handle the closer's duties. Smith has spelled Street for stretches the past two seasons, getting 15 saves in 2014 and five last year.

"It's never a good thing when you lose your closer," Smith said. "But that's why there's seven of us (relievers) out there. Everybody has to step up and do a little bit more than you were asked for before. Just be ready to go. We've got guys that are capable of doing it."

NOTES: Angels LHP Andrew Heaney will seek further medical opinions on his injured left arm because the healing process has been slower than expected. The first of two MRIs showed a strained flexor muscle in his left forearm, relatively good news because no ligament damage was discovered. However, his recovery has plateaued, according to manager Mike Scioscia. ... Royals CF Lorenzo Cain was not in the starting lineup for the first time this season, getting a day off in an effort by manager Ned Yost to help Cain relax. Cain was batting .162 (6-for-37) in his past 10 games with no extra-base hits. ... One night after getting three hits, including a game-breaking, three-run homer, Angels 2B Johnny Giavotella was on the bench in favor of Cliff Pennington, a switch hitter. ... Royals 1B Eric Hosmer homered in the first inning, extending his hitting streak to a career-best 17 games. It is the longest streak in the American League this season.