Colorado had scored a combined 14 runs to beat the Dodgers on Saturday and Sunday, only to find itself in a pitching contest Monday. But in addition to being shut out for the fourth time this season, the Rockies also ended the night uncertain about the status of right-hander Tyler Chatwood, who has given the pitching staff a lift since being called up from Triple-A Colorado Springs.
Chatwood (3-1) left after pitching four innings and batting in the fifth because of right triceps soreness. Chatwood gave up one run on four hits, struck out four and walked one. The run came after Jay Bruce singled with two out in the fourth, stole second and scored on Todd Frazier's single. Chatwood, with a 2.14 ERA in six starts, believes he will make his next outing. He hated bowing out of Monday's game, however.
"It's frustrating having to come out of the game like that and kind of leave the bullpen hanging like that, but it was precautionary," Chatwood said.
Rob Scahill replaced Chatwood and threw three scoreless innings. Bruce hit his ninth home run of the season -- a two-run shot -- in the eighth off Josh Outman.
Arroyo (6-5) struck out three, didn't walk a batter, and held the Rockies to four singles -- two off the bat of Carlos Gonzalez.
"I didn't particularly have amazing stuff, but it was one of those games where things just worked out," Arroyo said.
Reds manager Dusty Baker said, "That's a tough club to shut out over there. I mean, those guys can hit. We didn't know exactly when they were going to break out and figure it out, because like I said, they have some quality hitters over there. Bronson was masterful."
Gonzalez and shortstop Troy Tulowitzki entered the game hitting better than .500 off Arroyo, and first baseman Todd Helton was hitting .364 off the righty, but none of that mattered Monday.
"He threw the ball well tonight," Helton said. Same old guy, just kind of slings it up there. The ball's moving a lot. But we needed to go deeper in some counts and some at-bats and make him work a little bit harder. But those pitches are tough to lay off on."
Home-plate umpire Kerwin Danley was injured when a Chatwood pitch to Shin-Soo Choo in the bottom of the first bounced in front of catcher Wilin Rosario, ticked off Rosario's left shoulder and hit Danley in the mask.
Danley, who exited a Rockies-Dodgers game in 2008 when a pitch by Dodgers righty Brad Penny struck him in the mask, and was knocked unconscious by a broken bat a year later, was attended to by the Reds' training staff. Danley left the game after the bottom of the second, and Lance Barksdale took over home-plate duties for a crew reduced to three.
"I had a little headache," Danley said. "I'm just day to day. I hope to be back Wednesday. It was just a precaution. I had a concussion about two weeks ago. I don't remember who the batter was. It is just a little headache. I don't have any more to add."
The Rockies' Michael Cuddyer singled with one out in the seventh. The next hitter, Helton, hit an Arroyo pitch that appeared to bounce before making contact with Helton's bat. Third baseman Frazier caught it on the fly and threw to first to double up Cuddyer. However, the umpiring crew believed the ball hit the ground after it hit Helton's bat, so Cuddyer was allowed to stay on second.
"We ruled it a ground ball," crew chief Gary Cederstrom said. "It hit the bat first. By looking at replay, it looked like the ball hit the ground. The ball hit the ground. The bat hit the ball. Then the ball went in the air. We had a lot of things happening.
"We deciphered on the field that it was a ground ball ... that the ball was hit off the ground into the air."
Frazier figured a regular crew might have had a better chance.
"I guess eight eyes are better than six," Frazier said.
How tough a call was it? Helton didn't know it hit the ground before the bat, not the other way around, until he was asked about it.
"Oh, it did?" Helton said. "I didn't know. I knew it hit the ground sometime. I didn't realize it hit the ground before I hit it."
The call nearly cost the Reds, but Bruce ranged into the right-field corner to catch Rosario's drive in the next at-bat. At least it was good contact off Arroyo.
"We took some good swings. I thought Dexter [Fowler] hit the ball well," Rockies manager Walt Weiss said. "It was good to see Wilin hit a ball hard the other way that Bruce made a play on. He's tough, Arroyo."
Aroldis Chapman (15 saves) struck out three in a scoreless ninth.