Danley was hit in the mask under the jaw on the first pitch of the fourth inning, when a fastball from Penny to Garrett Atkins glanced off the mitt of catcher Russell Martin.
"It sounded like a Mike Tyson uppercut," said Martin, who said he called for a curveball but got a fastball from Penny.
"Before putting my head down," said Penny, pantomiming the way he looks at the ground early in his windup, "all I saw was fastball away."
Danley lay on his back behind the plate and was unconscious for a few seconds while Dodgers medical personnel attended to him. By the time he was lifted onto an ambulance, Danley was coherent, breathing and conscious.
"He looked like he was in pain for a little while," Martin said. "I hope he's all right. I told him I was sorry a couple of times, but I'm not sure he heard me. ... I was hoping for the best. He was still breathing. I held my breath."
Penny reflected on another poignant aspect of the scene. "What's hard is his mom was there," the pitcher said. "He's a great guy. It's unfortunate."
Los Angeles is Danley's hometown.
Penny (4-2) surrendered a two-run home run to Atkins in the first inning before the Dodgers sent 13 men to the plate in their half against left-hander Mark Redman (2-2). (The last time Los Angeles scored 10 runs in an inning came in the first inning of a May 6, 2005, game at Cincinnati.)
Manager Joe Torre was most impressed that "we scored all the runs with two out."
Matt Kemp ignited the fireworks with a sacrifice fly in his first at-bat, and later finished the rally with the first grand slam of his career, capping the first five-RBI game of his 172-game Major League career.
"I was just looking for a pitch to drive," Kemp said, adding later, "The first grand slam was pretty exciting and it helped us get some momentum."
Between Kemp's two plate appearances in the first, Andruw Jones walked to drive in a run, Blake DeWitt singled home two more, Penny chipped in an RBI single, and Rafael Furcal added an RBI double in his second time up.
Kemp said that although the huge rally was refreshing for a team still two games below .500, there was no way he or any Dodger was going to think of 10-2 as a cushion.
"The Colorado Rockies can put up just as many runs as we did," Kemp said.
Kemp's remark fit well with Torre's assessment of Penny's persistence, a word that might sound out of place in the story of a romp. But as Torre put it, "When you throw strikes, you make them beat you. [Penny] never let up. He's not going to, because he's got Russell reminding him every inning in the dugout."
Torre fielded a question regarding whether Kemp had emerged as a bona fide Major League hitting star.
"He's still raw," said the manager, who played 18 years in the big leagues (1960-1977), is in his 27th season as a manager and holds the Major League record for postseason victories, including four World Series championships.
"He has a great deal of ability. To play this game on an everyday basis, you've got to work at it."
Translation: He's in his third year and is off to a nice start.
In the sixth, Todd Helton's single pushed across the Rockies' third run off Penny, who went seven innings, surrendering four hits, striking out two and walking two before Scott Proctor came on in the eighth.
Asked what was working for him, Penny said, beaming, "The offense!"
Redman went six innings, yielding 10 earned runs on seven hits, giving up five walks and striking out one.
Right-handed reliever Jose Capellan came on for the Rockies in the seventh, and gave up the Dodgers' 11th run on Delwyn Young's pinch-hit single.
Ted Brock is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.