Osuna earned the win in his first appearance with Houston after Marwin Gonzalez hit a three-run homer with two outs in the ninth inning, lifting the Astros over the San Francisco Giants 3-1 on Monday night.
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Osuna (1-0) hadn't pitched in the majors since May 6 while serving a 75-game suspension for violating MLB's domestic violence policy. The former Blue Jays closer was arrested and charged with assaulting his girlfriend May 8 in Toronto. Few details have been made public, and the next court date in the case is scheduled for Sept. 5.
"Especially, like, being in such a great team with great teammates, it's easy to forget about the stuff that's going on off the field, and being able to play and help the team win is unbelievable," Osuna said. "I really like my teammates. They've been treating me with a lot of respect, and I'm really comfortable."
Osuna was acquired from Toronto last Monday in a deal that sent back closer Ken Giles, and he became eligible to pitch Sunday. A few fans booed when he entered the game in the eighth inning, and Osuna calmly retired the side in order.
"It was a quick look, obviously, with five pitches," manager A.J. Hinch said. "He's got a good arm. First game back is always important. It's the next step for him to get incorporated into our games, coming away with the win. A good first impression on the field."
Hector Rondon closed out the 2-hour, 26-minute game with his 12th save in 15 chances.
San Francisco closer Will Smith (1-2) blew his second save in nine opportunities after issuing walks to Alex Bregman and Yuli Gurriel. Gonzalez followed with a towering drive to left for his 10th homer.
Brandon Crawford hit a solo homer in the sixth inning, but San Francisco failed to do enough to back rookie Dereck Rodriguez's latest gem.
The two starters had a nice duel but nothing to show for it.
Rodriguez struck out seven with no walks and allowed three hits in seven innings. Charlie Morton, a 12-game winner, struck out eight over seven innings with three walks and three hits.
The Giants lost for just the third time on days Rodriguez starts - and this marked just his 11th in the big leagues. The son of Hall of Famer Ivan Rodriguez has quickly emerged as one of the top rookies in the National League.
Rodriguez has allowed three or fewer runs in 10 of his starts.
"I take it in after every start. I enjoy it, I think about it a lot of the time but when I'm out there it's just me, Buster (Posey) and the hitter, whoever's hitting, so I think that's what's helped me get to the point where I'm at, my concentration when I'm in the game," Rodriguez said. "It's awesome being in the situation I'm in."
Astros third base coach Gary Pettis attended 49ers practice to see son, Dante, a second-round rookie wide receiver out of Washington.
A concession stand caught fire approximately three hours before first pitch near section 121 on the main concourse of AT&T Park. The blaze was out by the time the fire department arrived, there were no expected delays and no fans had been let inside yet, according to Jorge Costa, Giants senior vice president of ballpark operations.
"This happens occasionally," he said.
Astros: World Series MVP and All-Star outfielder George Springer went on the 10-day disabled list with a left thumb sprain he hurt during Sunday's loss to the Dodgers on a headfirst slide. ... SS Carlos Correa, recovering from lower back soreness, was off from his rehab assignment and scheduled to play nine innings both Tuesday and Wednesday for Double-A Corpus Christi before being activated when the Astros start their homestand. ... RHP Lance McCullers Jr. (right elbow discomfort) won't pitch until September, if at all. There's no timetable for when he could begin throwing, Hinch said. ... RHP Chris Devenski (left hamstring tightness) was examined by a doctor and will throw a bullpen later this week once the team returns home. ... C Brian McCann (right knee soreness) caught Justin Verlander's bullpen Monday.
Giants: 1B Brandon Belt, sidelined by a hyperextended right knee, hit early batting practice and took groundballs. Manager Bruce Bochy doesn't expect Belt will need a rehab assignment. "The progress is going well for him right now," Bochy said. ... RHP Jeff Samardzija (inflammation in his pitching shoulder) threw 30 pitches in a bullpen and is scheduled for another mound session Thursday before throwing to hitters at Los Angeles on Monday. ... Bochy spoke to INF Pablo Sandoval on Monday before the 2012 World Series MVP undergoes season-ending surgery Tuesday on his torn right hamstring. "Bad break for him, bad break for us," Bochy said. "He's a big part of this club, his energy, his passion that we're going to miss. He was a little down."
Astros: LHP Dallas Keuchel (9-9, 3.61 ERA) lost his only previous start vs. San Francisco.
Giants: LHP Madison Bumgarner (4-4, 2.97) needs one victory for fourth place on the San Francisco wins list. He has won his last four starts against the Astros with a 1.20 ERA but hasn't faced Houston since a five-hitter with 12 strikeouts on Aug. 11, 2015.
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