DENVER -- The Chicago Cubs' future looks bright even if their present is a little disappointing.
The Cubs' 21-year-old prized prospect became the first MLB player with three homers in his first three games since Joe Cunningham in 1954.
He also became the first Cubs player since 1900 to post a multihomer game in his first three games.
Baez, who also had an RBI single, homered in his debut Tuesday, hitting a game-deciding shot in the 12th inning on the day he was promoted from the minors.
"It didn't surprise me too much," said Hendricks, who had the best outing of his short career. "I've seen it for a couple of years and he always thrives on the big stage. Whenever we play in a big game he does well."
The Cubs (49-64) closed out a six-game trip by taking two of three in the series between last-place teams.
"I was letting the fastball get deep and he threw me a slider," Baez said of his second drive. "I hit it really good."
Castro followed Baez's shot in the sixth with his 12th home run. It was the fourth time this season Chicago has hit back-to-back homers.
Hendricks (3-1) pitched a career-high eight innings after the start of the game was delayed 39 minutes because of rain. The rookie right-hander has pitched into the seventh inning in four of his five career starts.
"He's a very poised young man and he's the type of kid when he prepares for the test he knows he's going to do well," Cubs manager Rick Renteria said. "I hope he's making believers out of a lot of people."
The 24-year-old Hendricks was sharp against the Rockies, allowing just two runs and six hits. He didn't allow a runner until Charlie Blackmon's leadoff single in the fourth.
After Baez and Castro gave Hendricks a three-run cushion in the sixth, the Rockies scored on Corey Dickerson's RBI single in the bottom half. Hendricks retired the last seven batters he faced.
"I felt really good," he said. "Usually as the game goes on I get stronger and stronger."
The Cubs took a 2-0 lead against Flande with RBI singles by Arsmendy Alcantara in the second and Baez in the third. Colorado cut the lead in half on Morneau's RBI single in the fourth.
Flande is still looking for his first career win despite two solid outings against Chicago. He struck out a career-high eight in a 4-1 loss to the Cubs on July 28 and lasted six innings Thursday.
"I pitched was well as I could. Something always happens to me in the late innings," Flande said. "I'm disappointed."
Hendricks was thinking after seven innings he had a chance for his first complete game. Two batters into the eighth he knew it wasn't going to happen.
"I went into the eighth at around 91 (pitches) and after I went full count on the first two hitters that kind of went out the window," he said. "I was trying to get quick outs but I was almost aiming it in there so I could go out for the ninth."
Cubs: First baseman Anthony Rizzo was given a rare day off with the left-hander Flande on the mound. It was just the second day off for Rizzo, who is second in the NL with 25 home runs.
Rockies: Shortstop Troy Tulowitzki (left hip flexor strain) has begun baseball activities and will travel to Arizona and San Diego with the team. Tulowitzki is eligible to come off the 15-day disabled list but hasn't been running at full speed. Manager Walt Weiss said that will be the final hurdle for the major league batting leader.
Cubs: Left-hander Tsuyoshi Wada (1-1, 3.32 ERA), like Hendricks on Thursday, is making his fifth career big league start when he faces Tampa Bay on Friday. He has held opponents to a .259 average in his first four starts.
Rockies: Lefty Tyler Matzek (2-6, 5.31 ERA) will try to rebound from a rough outing in Detroit last weekend when he faces Arizona on Friday. Matzek is one of four Colorado starters to make his major league debut this year, and he has been impressive at times. His outing against the Tigers was the only start in which he failed to go at least five innings.
Information from ESPN Stats & Information was used in this report.