GOODYEAR, Ariz. (AP) — Homer Bailey thought the numbers looked a lot worse than he pitched.

Jesus Montero hit a grand slam, Michael Saunders homered among his three hits and the Seattle Mariners hammered Bailey in a 16-0 rout of the Cincinnati Reds on Monday.

Saunders connected off Bailey, and Justin Smoak added two hits off the right-hander, driving in three runs. Montero’s slam came off Wilken De La Rosa, one of two non-roster pitchers left in Reds camp.

Bailey was scheduled to pitch five innings but lasted only 3 1-3, allowing nine runs on nine hits and two walks. He struck out five.

“It was their day, not mine,” Bailey said.

The Reds let two fly balls drop while Bailey was on the mound and committed an error.

“I don’t think it was as bad as the line looks,” Bailey said. “They hit that one home run but other than that, there were a lot of ground balls that went through, dropped balls. I made some good pitches and struck a few guys out, but it seemed like every time they put it in play there was a runner on.

“I think the catcher (Montero) hit a couple of them up the middle, some broken-bat hits. It’s kind of frustrating sometimes.”

Saunders also doubled, singled and scored three times from the leadoff spot. He was named to the all-WBC team as a member of Team Canada.

Montero was 3 for 3 and is hitting .405 with 10 RBIs this spring, including six on Monday.

Brandon Maurer continued to impress the Mariners. He gave up six hits and a walk in five innings, striking out seven. The 22-year-old is making a strong case to earn a spot in Seattle’s starting rotation.

Selected by the Mariners in the 23rd round of the 2008 draft, Maurer is testing manager Eric Wedge’s resolve to keep the competition going.

“We are trying to go all the way through. Part of my discipline is keeping my mind open to the very end,” Wedge said. “The very end is approaching quickly here. We’ll see how the next couple days play out, but it’s safe to say we are close to making a decision.”

Maurer made his case on the mound.

“I can’t think about competing for the spot,” Maurer said. “I just have to concentrate on going out there and getting ready for the next start. Those guys can hit.”

Maurer used his changeup and curve, two pitches that needed work coming into camp.

“It was nice to go out and have a little confidence in them,” he said.

The outing lowered Maurer’s spring ERA to 0.90. He has allowed two earned runs in 20 innings. He also pitched out of a bases-loaded jam on Monday.

“Maurer threw the ball very well against a good group of hitters,” Wedge said. “Pitching out of that situation isn’t something we haven’t seen. It reaffirms what we’ve seen. For him to pitch the way he pitched and have the time he sat on the bench today and still be effective was very impressive.”

Jack Hannahan and Zack Cozart doubled, and Brandon Phillips tripled among the Reds’ seven scattered hits.

“We looked kind of pitiful,” manager Dusty Baker said. “We didn’t catch. We didn’t hit. Nothing. Homer didn’t throw the ball that bad. They got some two-out hits. We didn’t help him on defense.”

NOTES: Reds RHP Bronson Arroyo threw some pitches to test his right hand. Arroyo was hit on his pitching hand by David Murphy’s comebacker Sunday against Texas. X-rays were negative. Arroyo is expected to make his final spring start on Friday. … INF Jason Donald will get some at-bats in minor league camp. He is out with a sore knee. Donald is one of three players competing for the Reds’ final utility role. … The Mariners placed RHP Josh Kinney on the 60-day disabled list, then added Kameron Loe to the 40-man roster. … Saunders’ homer was his third of the spring. Montero has two grand slams this spring.