PEORIA, Ariz. -- San Diego Padres rookie first baseman Yonder Alonso feels as if he is just starting to get comfortable at the plate.

The Padres hope Saturday's performance is a sign of things to come.

Alonso hit a three-run double in the first inning and singled as the Padres topped the Kansas City Royals 8-5.

Alonso is one of four players the Padres received in a Dec. 17 deal that sent pitcher Mat Latos to the Cincinnati Reds.

Alonso thinks he is seeing the ball better and his timing has improved.

"Every day feels better," Alonso said. "I'm just trying to lock in with the guys. It's time to go. It's time to roll."

Manager Bud Black thinks the Padres will see improvement from Alonso shortly.

Alonso is hitting .286 with seven RBIs through his first 35 at-bats this spring. Black liked Alonso's approach against Royals pitcher Bruce Chen in the first inning when he lined a first-pitch changeup off the right-field fence to give the Padres a 3-0 lead.

"That was good aggressiveness," Black said. "We've seen him hit it off the right-field wall, the left-field wall and the center-field wall. His spring average is not what we thought it would be, but we're not concerned."

Chen's spring ERA is not where he'd like it to be.

Chen said his arm feels good and pointed to his 66 pitches thrown as evidence. But how Chen felt didn't keep him from getting hit hard for a second time in three outings this spring, an outing that saw his ERA increase from 9.64 to 11.74.

Chen, who was 12-8 with a 3.77 ERA in 25 starts for the Royals last season and figures to be among the team's top three starting pitchers in 2012, allowed five runs and eight hits in three innings. He also struck out two.

The left-hander said he adjusted well after he allowed five runs in the first inning. Chen allowed three hits in his final two innings, but stranded two runners on third base.

"My arm feels great, my stamina feels good, I have no pain in my arm," Chen said. "I feel very strong. Right now I'm not making pitches. So I only have to work on keeping the ball down and making better pitches. But everything else is there."

Padres starter Cory Luebke thought he did a better job of keeping the ball down, and for the most part he did.

Luebke and Padres pitching coach Darren Balsley made an adjustment in a bullpen session two days earlier.

While he did leave one pitch up in the zone that Kansas City's Alex Gordon blasted for a 410-foot single, Luebke felt good otherwise. He allowed a pair of runs, six hits and struck out four in four innings.

"Most of the balls up in the zone were intended to be up," Luebke said. "Out of the stretch is where we wanted to keep the ball down and we did it. It was an easy fix."

Right fielder Jeff Francouer went 2 for 3 and designated hitter Billy Butler had an RBI single for the Royals. Cameron Maybin doubled and walked for the Padres in four trips to the plate. Will Venable went 1 for 4 with a run scored for San Diego.

Huston Street and Andrew Cashner pitched scoreless innings for the Padres.

Game notes
The Padres said they have rescheduled Sunday's split-squad game against the Colorado Rockies in Tucson for Thursday afternoon. ... Padres C Nick Hundley missed his third straight game with a sore right side, manager Bud Black said. Hundley said the Padres are just being cautious and the injury isn't severe. Hundley, who missed a month last season with a right oblique strain, expects to return Tuesday. ... Padres 2B Orlando Hudson (groin strain) resumed baseball activity on Saturday and could return to the lineup in the middle of the week, Black said. Hudson was scratched from Thursday's lineup and hasn't played since Tuesday.