SAN FRANCISCO -- After three days at Coors Field, the Pirates called up Clay Holmes to make one start and provide extra rest for their rotation. But their decision backfired on Friday night as the rookie right-hander struggled in his abbreviated return to the big leagues.
Holmes allowed seven runs on eight hits and four walks over 2 2/3 innings in the Pirates' 13-10 loss to the Giants at AT&T Park. Pittsburgh lost ground in the National League Central and Wild Card races, falling to eight games behind the Cubs and five games out of a Wild Card spot.
"The overall command, the inconsistency of his stuff -- it just didn't show up very well tonight," manager Clint Hurdle said.
It was an unusual move for the Pirates to call up Holmes from Triple-A Indianapolis to make his third Major League start in the middle of a postseason race. The plan had been in the works for weeks, and Holmes knew after his last start -- before Hurdle's unexpected announcement on Thursday afternoon -- that he was bound for another big league start.
Holmes showed promise in his last outing, working six scoreless innings against the Brewers on July 14, but he is unproven compared to the Bucs' current five-man rotation. And pitching has been the least of Pittsburgh's problems lately, as the Pirates entered the night with an NL-best 3.05 ERA since July 7.
Right-hander Trevor Williams, who has allowed two runs over his last four starts, could have started Friday's game on regular rest. Instead, the Pirates pushed their five starters back a day -- mostly to benefit those who pitched earlier this week at Coors Field -- and inserted Holmes into their rotation.
Holmes struggled from the start, lacking the stuff and command he displayed against the Brewers. His sinker averaged 93.3 mph on Friday night compared to 95.6 mph in his last big league start; catcher Francisco Cervelli said the velocity drop may have been the result of Holmes trying too hard to throw perfect pitches. Holmes threw only 33 of his 63 pitches for strikes, and the Giants swung and missed only twice against him.
"You have to be ready when your name's called," Holmes said. "I just didn't make enough quality pitches tonight and wasn't at my best tonight. There's really no excuses."
Andrew McCutchen hit a leadoff home run before Austin Slater and Alen Hanson each drove in a run in Holmes' 25-pitch first inning. After a quiet second inning, the Giants loaded the bases with two outs in the third before Holmes walked McCutchen to bring home a run. Buster Posey then smacked a two-run single to center, ending Holmes' night.
Perhaps the Pirates' decision to temporarily carry six starters will benefit Joe Musgrove, Jameson Taillon and Chris Archer when they pitch over the next week. But it also left them with a six-man bullpen: their five high-leverage relievers and long reliever Casey Sadler. So when Holmes exited early, Sadler had to bear the brunt of the remaining workload -- and bat twice with runners in scoring position -- as he allowed four runs over 3 1/3 innings.
"I felt comfortable going in [with six relievers]. Obviously the game can change things as you go," Hurdle said. "That was a decision we made beforehand, though, understanding that sometimes it works, sometimes it doesn't."
Hanson led off the fourth with a single against Sadler, then Joe Panik and Steven Duggar hit back-to-back doubles to give the Giants a 9-2 lead. Posey punctuated the rally with his fourth hit in as many innings, an RBI single to center. Brandon Crawford led off the fifth with a double to deep center and scored on Hanson's groundout to second base.
The Pirates managed to rack up 10 hits against Giants left-hander Derek Holland, and Cervelli's seventh-inning grand slam off reliever Pierce Johnson cut their deficit to four runs. Colin Moran hit an RBI triple off Tony Watson and scored on a single by Cervelli in the eighth, and Adeiny Hechavarria homered in the ninth to make it a three-run game. But the early hole proved to be too much for Pittsburgh overcome.

"We're tough. We don't give up," Cervelli said. "That's the way we are, because we're chasing something and we're not going to give up."
MOMENTS THAT MATTERED
No relief: After Holmes and Sadler pitched and Cervelli made it a four-run game in the seventh, the Pirates turned to the back end of their bullpen. Kyle Crick, pitching in his former home ballpark for the first time, hit Evan Longoria with a 97-mph fastball, then gave up an RBI double to Hanson in the seventh. The Pirates then cut the Giants' lead to three runs, but Richard Rodriguez walked the bases loaded before giving up an RBI single to Slater.
"Our command was pretty inconsistent throughout the evening," Hurdle said.

SOUND SMART
Cervelli's fourth career grand slam gave him 46 RBIs on the year, a single-season high mark for the catcher. He drove in 43 runs in 130 games for the Pirates in 2015.
Moran's eighth-inning triple snapped his streak of 20 straight singles. It was Moran's first extra-base hit since July 9 and his second career triple.

HE SAID IT
"He pitched in a big series against Milwaukee, too. Pitched amazing. I don't know. ... He's got a long career, man. He's going to be fine. That guy's going to be amazing." -- Cervelli, on Holmes being asked to come up and pitch in a postseason race
UP NEXT
After the Giants retire Barry Bonds' number in a pregame ceremony, Williams will take the mound at AT&T Park. Williams has allowed only two runs over his last four starts, both of which came in his last start against the Cardinals. That outing snapped Williams' three-start/17-inning scoreless streak. First pitch is scheduled for 9:05 p.m. ET.