Arrieta gave up three hits over four scoreless innings and struck out five, then went to the bullpen to finish his pitching duties. The right-hander took advantage of batting eighth, a strategy manager Joe Maddon has been experimenting with this spring.
"It is the pitcher, and it seems like a break in the lineup, but we feel we can do some damage there and help us out," Arrieta said.
The Cubs sent 11 batters to the plate in the first. Anthony Rizzo reached on a fielding error by second baseman Charlie Culberson, advanced to third on Bryant's double off the right-field wall, and then scored when catcher Michael McKenry's attempted pickoff throw skipped into left field.
Bryant tallied on Addison Russell's bunt single as starter Jon Gray bobbled the ball. Ryan Sweeney hit an RBI single, and another run scored on David Ross' suicide squeeze, which Gray again had trouble handling. Arrieta then launched his first spring homer to left for a 7-0 lead. Gray struck out Jonathan Herrera, and was lifted.
Gray, the Rockies' first-round pick in 2013, gave up seven runs -- six earned -- on four hits and one walk over two-thirds of an inning.
"I just didn't feel like myself at all," Gray said. "I didn't get strikes early. I didn't give my team a chance. I think I was so worried about being in the zone that I left some too hittable."
Rockies left fielder Corey Dickerson exited before the top of the third with lower back tightness but insisted it's not a big deal. He said his back and hamstrings tightened during a long bottom of the first, when Gray struggled.
"Long inning," Dickerson said. "I fielded a ground ball and my lower back got tight. I just came out -- precautionary. I was up to bat that inning and didn't want to do anything to hurt myself."
Dickerson was scheduled to go with the Rockies' split-squad team that will travel to Hermosillo, Mexico, on Sunday to face a D-backs' split-squad.
Up next: We'll have to see if Edwin Jackson takes the team bus or drives himself on Sunday. Jackson, who went to the wrong ballpark in his last start, is scheduled to start Sunday when the Cubs face the Royals in Surprise. The game can been seen live on MLB.TV and listened to live on Gameday Audio. First pitch is scheduled for 3:05 p.m. CT.