Lough, who was ranked No. 18 among the Top 20 Royals prospects, was batting .275 in 130 games for Triple-A Omaha with 19 doubles, 11 triples and 10 home runs. He had 69 RBIs and 26 stolen bases in 30 attempts.
Lough will help fill the void caused by outfielder Jarrod Dyson's lat strain, which hampers Dyson's throwing and will limit his playing time.
Lough, 26, has never played in the Major Leagues. He was an 11th-round Draft choice of the Royals in 2007. A left-handed batter, he's spent the past three seasons with Omaha and had a .318 average in 2011.
"It's been a long ride, but I'm just happy to be up here," Lough said. "It's a slow process for some guys and I know I needed to work on some things. [The team] took it slow with me, and I don't feel like I should've been here years ago or anything like that. But I'm ecstatic, I really am."
Lough has been working on upping his stolen base total and this year he has 26 steals in 30 attempts. In each of his previous two years, he had 14.
"They've really preached to me about not being afraid to take the extra base when I get the opportunity, and this year I feel a lot more confident on the base paths and have been able to rack up a few [steals]," Lough said. "It's definitely something I wanted to focus on this year."
Lough played mostly in right field this year, although he recently switched to center when top prospect Wil Myers was moved to third base for a trial run at that position.
"[Myers'] first couple games he looked a little rough and threw one in the stands, but other than that, he's been solid and making good throws," Lough said. "He's looking pretty sharp."
Pina, 25, began the season on the disabled list after undergoing surgery on his right knee during Spring Training. His rehabilitation was slowed for a while by a hip flexor problem.
After a brief stay with the Rookie club at Surprise, he was assigned to Double-A Northwest Arkansas, where he hit .260 in 43 games with five homers and 20 RBIs.
"I was playing five, six days a week and I feel really good," Pina said.
Last season Pina was with the Major League club twice briefly, playing in four games with a .214 average. He was acquired by the Royals from the Rangers in a Minor League trade in 2009.
Pina will wear uniform No. 28 and Lough No. 7.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.