SAN FRANCISCO (AP) — Rookie Casey Kelly had been in control since being called up from the minors by the San Diego Padres last month.
That's why his struggles to find the strike zone on Friday night were so surprising to manager Bud Black.
Kelly walked four batters to match his total from his first four starts and couldn't make it out of the fifth inning as the Padres lost 5-1 against the San Francisco Giants.
Kelly (2-2) hadn't walked a batter his past two starts but both runs he allowed against Giants came on batters who reached with free passes. He allowed seven hits in 4 1-3 innings.
"It was uncharacteristic of Chris to walk so many," Black said. "They came back to get him. The ball-strike ratio wasn't very good. His pitches were around the zone. He wasn't wild but couldn't hit his spot. That came back to haunt him."
Buster Posey hit a tiebreaking RBI single off Kelly in the fifth inning after being honored in a pregame ceremony with the "Willie Mac" award as the most inspirational player on Giants.
The hit came after Marco Scutaro drew a leadoff walk. The Giants also scored in the fourth after Brandon Belt drew a one-out walk.
"Walks are the thing that are going to kill you." Kelly said. "I had a bunch of them today. I wasn't getting ahead tonight. But I got some confidence working out of some of those jams though. I learn every time out every inning. It just makes me better for the next one."
Ryan Vogelsong (13-9) allowed one run in six innings match his career high in wins and put the Giants in position to clinch a division title as early as Saturday. San Francisco would win the West on Saturday night with a win if the Los Angeles Dodgers lose earlier in the day to Cincinnati.
"It's in our hands," manager Bruce Bochy said. "When you're in this situation you want to go out there and take care of business. You want to get in through the front door not the back door."
Pablo Sandoval belted his fourth home run in three days, and Brandon Crawford and Scutaro had RBI singles as San Francisco matched a season high with its fifth straight win.
Chase Headley hit a solo shot for his 29th homer for the Padres. But he was thrown out at home trying to score the tying run on Yasmani Grandal's two-out double in the sixth. The Giants cut him down with a well-executed relay from left fielder Gregor Blanco to Crawford to Posey, who fielded the throw on a short hop and tagged Headley to preserve a 2-1 lead.
"We really didn't swing the bats very good tonight against Vogelsong," Black said. "Other than Chase, we really didn't threaten them. Vogelsong did a nice job. His curveball was working tonight as was his changeup. We couldn't mount any pressure."
The Giants broke it open with three runs in the sixth, capped by Sandoval's homer. After going 161 at-bats without a long ball, Sandoval has regained his power stroke this week and now has 12 homers this season.
It was a big day all around for Posey, who won the award named after Hall of Famer Willie McCovey that is voted upon annually by Giants players, coaches, training staff and the fans.
Posey also got a boost in his bid to win the batting title when teammate Melky Cabrera requested to be disqualified from the NL honor. Major League Baseball and the players' association agreed to a one-season-only change in the rule governing the individual batting, slugging and on-base percentage champions.
Serving a 50-game suspension after testing positive for testosterone, Cabrera leads the league with a .346 average. Cabrera had 501 plate appearances, one short of the required minimum if the Giants play 162 games, but would have won the title under section 10.22(a) of the Official Baseball Rules if an extra hitless at-bat were added to his average and he still finished ahead. With Friday's agreement, that provision won't apply this year to a player who "served a drug suspension for violating the Joint Drug Program."
Posey, who is hitting .335, trails Pittsburgh's Andrew McCutchen by three points for the NL lead with less than two weeks left in the regular season.
NOTES: Headley's 21 HRs since the All-Star break are the second-most in San Diego history, trailing the 28 by Ken Caminiti in 1996. ... The Padres reinstated closer Huston Street from the DL before the game. He had been out since Aug. 11 with a strained left calf. ... Grandal left the game in the seventh inning after taking a foul ball off his mask. ... Madison Bumgarner (15-10) starts the middle game of the series on Saturday against San Diego's Andrew Werner (2-1).