SAN FRANCISCO (AP) -- Tyler Beede had some of the best stuff he's shown on a day that ended in disappointment.
Beede, a 26-year-old rookie right-hander, grabbed his left side after striking out Ryan McMahon leading off the fourth. Beede was replaced by Burch Smith, who allowed the Rockies to tie the score in the fifth.
Beede had an MRI on his left oblique, the results of which weren't immediately available.
''It's too bad, really, what a bad break,'' Giants manager Bruce Bochy said. ''That's as good a stuff as he's thrown all year, really locked in with all his pitches. I was kidding him, it probably wasn't good timing, 'But you know you've got a no-hitter going here, you want me to take you out?'''
''I'm sure he was disappointed because he really was locked in with all his pitches,'' he said.
Dubon, a 25-year-old rookie acquired at the trade deadline from Milwaukee, had a tiebreaking single in the bottom half off Jesus Tinoco (0-3), then hit his fourth homer for a 4-2 lead in the seventh against Sam Howard.
''We had a one-run cushion, so it was pretty huge,'' Dubon said. ''I was happy to contribute. That's the main thing when you play this game is you want to be a contributor, that's how I felt today.''
Yastrzemski entered as a pinch-hitter in the fourth and hit his 21st homer, a solo drive off Tinoco, for a 2-1 lead. Yastrzemski had an RBI double in a four-run seventh that included a two-run single by Aramis Garcia.
Sam Coonrod (5-1) allowed one hit in 1 1/3 scoreless innings.
Rockies starter Kyle Freeland gave up one run and three hits in three innings in his second game back from the injured list with a left groin injury.
''Overall it was a fine outing,'' Rockies manager Bud Black said. ''I think since he returned he's throwing better. And even though it's been just two outings, his (changeup) has been better.''
Colorado has lost six of eight after a four-game winning streak. Yonathan Daza singled leading off the fifth to stop an 0-for-20 slide.
Rockies hitters struck out 16 times, raising their total to 47 in the three-game series.
Bochy acknowledged this weekend's home series against the rival Los Angeles Dodgers is a proper way to conclude his career.
''All the battles I've had with LA - key games, important games, games that have gone to the wire at times - I guess it is fitting that I'll wrap up things against them,'' Bochy said. ''As a I look across the field at the Dodgers, it's going to be a lot of reflecting for me in that series.''
Rockies: RHP Jeff Hoffman, hit by a line drive Tuesday around his right knee, has been cleared to start Sunday against Milwaukee. ... RHP Peter Lambert threw a bullpen session on Thursday. The 22-year-old rookie will not pitch against this season.
Giants: RHP Johnny Cueto reported no issues after throwing a bullpen session on Wednesday and will start Friday. The two-time All-Start has thrown 14 innings in three starts since missing 13 months recovering from Tommy John surgery. ... RHP Logan Webb and LHP Madison Bumgarner will start San Francisco's last two games. ... RHP Trevor Gott had surgery on Thursday to treat a left groin injury. Gott is expected to be at full strength by spring training after a recovery of about six weeks.
Giants: Cueto (1-1, 2.57) is 7-8 with a 3.21 ERA in 19 starts against the Dodgers.
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