The Cubs' possible opening-day starter gave up two straight singles then, after a sacrifice bunt, hit a batter and walked the next in a rocky two-run third inning. In three innings, he gave up three runs and four hits.
"My arm is really coming along. It feels strong," Samardzija said. "I felt better in the third than in the beginning. The pitches were good. A few pitches were up, which got me in trouble. ... But I felt really good."
Samardzija said he is working on his repertoire of pitches, except for his splitter, which he is saving for later in March.
"The split essentially is just a fastball with a different grip. It's a good time for me to concentrate on my combination of other pitches," he said. "I just want to come out and establish my other pitches and really work on pounding the zone. We did that today. A couple hits fell and got through."
Rockies projected starter Tyler Chatwood gave up one unearned run in 2 2/3 innings. He walked two and struck out three.
The Rockies committed three errors behind Chatwood, who gave up only one hit.
Javier Baez, rated the No. 5 prospect by Baseball America, and George Kottaras connected for back-to-back homers in the sixth off the Rockies' Chris Martin.
Rockies: Chatwood gave up only one hit in his first spring start. He is coming back from offseason surgery to remove a bone chip from his pitching elbow. He was a pleasant surprise last season, going 8-5 with a 3.15 ERA in 111 1/3 innings.
"I felt 100 percent," Chatwood said after his start. "I haven't had any setbacks since I had the procedure done.
"A good outing for him," manager Walt Weiss said. "It's been smooth sailing. He hasn't had any issues."
Samardzija hit the Rockies' Michael Cuddyer in the left shoulder. The outfielder indicated he might miss a few days.
"It's a weird thing, Samardzija said. "All my pitches down and in to righties were so good. ... I was looking for a good one there. Hopefully he's OK. He's a heck of a hitter."
The Rockies committed five errors. Solid defense is a must in spacious Coors Field, and Weiss believes it will be there when it counts.
"We don't have all our guys out there (versus the Cubs), but we're a good defensive club," Weiss said.
Rockies: Jhoulys Chacin, the possible No. 1 starter for the Rockies, is set to start playing catch Thursday as he returns from shoulder inflammation.
The Rockies are hoping Chacin will be ready to pitch at some point in April, but he is likely to miss several starts.
"Hopefully it's just one or two starts," Chatwood said. "Any time you lose your number one, it's difficult.
"But we just have to handle our business. We can't put any more pressure on ourselves," he said. "As long as we throw the ball like we're capable, we should be just fine by the time he gets back."
Cubs: Travis Wood will start Thursday at Cleveland in Goodyear. For Friday's split-squad games, Edwin Jackson will start against Cleveland in Mesa and James McDonald will start at the Angels in Tempe.