MINNEAPOLIS -- Bad weather, poor performance and injuries led to a lot of questions about the Minnesota Twins' rotation.

At least for one game, a rookie was the solution Minnesota needed. Then more questions arose with right-hander Phil Hughes heading to the disabled list.

Robbie Grossman, Max Kepler and Chris Gimenez each homered for the Twins, and rookie Adalberto Mejia pitched seven strong innings in his return to the majors as Minnesota earned an 8-4 win against the Kansas City Royals to gain a doubleheader split on Sunday.

Mejia (1-1) entered the day as somewhat of an unknown. He was recalled from Triple-A Rochester as the 26th player for the doubleheader and gave up three runs on five hits to earn his first major league win.

"I thought he threw it over. I thought he was aggressive," Twins manager Paul Molitor said. "At times maybe he overthrew it just a little bit, but overall you've got to be pleased. You get seven innings and bounce back and win the second game after you let the first one slip away."

Grossman and Kepler each hit two-run homers in the first inning as Minnesota recovered to take the second game after losing 6-4 in the opener.

Hughes (4-3) allowed five runs on six hits and two walks in four innings in the first game and said he dealt with shoulder soreness starting in the second inning. He lost his second straight start and has allowed 14 earned runs in 13 2/3 innings over his past three starts.

The Twins announced after the game that Hughes would be headed to the disabled list as he receives further testing on the shoulder. Hughes missed the second half of last season after fracturing his femur and then having surgery on his pitching shoulder to relieve thoracic outlet syndrome.

Hughes said he is feeling the same symptoms with his shoulder that he did last year.

"It's very frustrating," Hughes said. "I thought, hopefully, that a lot of this was behind me. So, to have this sprout up again is frustrating. Hopefully, it's a somewhat easy answer and something I can bounce back from."

Mejia provided a big boost in the second game and possibly earned a chance to return the next time Minnesota needs a starter. Mejia started the season in the Twins' rotation but was optioned to Triple-A Rochester after posting a 5.79 ERA through three starts.

"It felt good," Mejia said. "I feel like I have more confidence. I went down to Triple-A to work my mechanics. ... I felt like that worked, and I felt good."

The teams combined for 10 home runs in the two games, six in the nightcap.

Saturday's game was rained out, leading to the rare straight doubleheader. Minnesota is 7-1 against Kansas City this season.

Royals Game 2 starter Ian Kennedy (0-4) only lasted two innings in his return from the disabled list. He gave up five runs on three hits and three walks.

"It's like throwing bullpens, throwing bullpens, and then going out there and trying to throw in a game with real hitters and in a game that means something," Kennedy said. "It's frustrating because you don't feel it, but your timing's off. Everything was off."

Kansas City's Salvador Perez hit two home runs in the second game of the twin bill and tied the franchise record for home runs in a doubleheader with three. Eric Hosmer added a solo homer for the Royals.

"I like hitting here," Perez said. "Everywhere I go, I try to do the best I can do to help my team to win. ... It's a good place for me, Minnesota."

Perez's second homer of the day put the Royals ahead 2-0 in the top of the first, but the Twins responded quickly against Kennedy. Brian Dozier walked and Grossman followed with a long homer to right-center field. Kennedy walked Miguel Sano before Kepler's high-arching shot to the overhang seats in right.

Kennedy had been out since May 4 with a right hamstring strain. Rookie Jake Junis, who started the opener, was optioned to Triple-A Omaha after the first game to open a roster spot for Kennedy.

Junis made his first major league start after being recalled from Triple-A earlier in the day with reliever Al Alburquerque designated for assignment. Junis pitched 4 2/3 innings and allowed two runs on five hits and three walks.

"You don't really have much time to think about it," said Junis, who learned about making the start on Saturday. "There's really not too much stress involved. I mean, there's stress flying and going all over the place, but I didn't have too much time to think. You've got to just go out there and pitch."

Kansas City won the first game behind four homers and the first major league win for Mike Minor (1-1) since Aug. 28, 2014. Brandon Moss had two solo homers among three hits in the opener. Kelvin Herrera finished off his ninth save.

NOTES: The Twins announced that RHP Kyle Gibson will be recalled from Triple-A Rochester to start Monday in Baltimore. Gibson will take Hughes' place on the roster. ... Sunday marked the first traditional doubleheader in Minnesota since May 26, 2001, at the Metrodome. It was Kansas City's first traditional doubleheader since Sept. 1, 2012, which was at home against the Twins. ... The Royals added RHP Miguel Almonte from Double-A Northwest Arkansas as their 26th player for the doubleheader. ... Kansas City OF Alex Gordon left the team following the first game to be with his wife, who is giving birth on Monday. Gordon was placed on the paternity leave list. The Royals recalled INF Raul Mondesi from Triple-A Omaha. ... Kansas City manager Ned Yost said RHP Nate Karns has some fluid near his pitching elbow and will continue to be evaluated. Karns left Friday's start after experience tightness.