If Buster Posey is the heart and Madison

Bumgarner the soul, what’s Brandon Crawford?

For starters, irreplaceable.

Posey and Bumgarner are the Giants’ franchise players, the marquee men who do the most on the field and get the most pub off it. The supporting cast has had different levels of value and importance this year, and it’s hard to rank anyone above Crawford.

A case could be made for Hunter Pence. But Pence has been a virtual no-show, limited to 52 games and serving three terms on the disabled list.

Crawford has had his best overall year, his value as a hitter catching up to his value as a fielder. The more he showed he could hit for power, hit in the clutch, hit to all fields against both righties and lefties, the more he moved up the lineup, from eighth to as high as fifth, even cleanup for a game.

Then he got hurt. Back when the Giants still were contending. He hasn’t been the same. Neither has his team.

“It’s tough,” Crawford said. “We still have a chance. We’re not counting ourselves out. But it was tough to go from only a few games back to, what, 8½ was the furthest? Do I think I could’ve helped a lot more if I was healthy? Yeah, I definitely think so. I definitely could’ve contributed.”

Crawford is expected to return to the lineup Friday when the Giants open a series against the Diamondbacks. He missed 15 of the past 21 games with oblique and calf ailments and wasn’t 100 percent in the six games he did play.

In that stretch, the Giants nosedived from 2½ games out of first place to 7½ back.

The beginning of the end — if indeed this is the end for the Giants — can be traced to Aug. 25 when they trailed by 1½ games and were to open a weeklong homestand with the intention of closing in on the Dodgers or overtaking them before flying to Los Angeles for a key three-game showdown.

The Giants still had faith in Matt Cain, who was coming off a rare decent outing, but Cain got rocked in an 8-5 loss to the Cubs and hasn’t pitched since. In the game, Crawford strained his left oblique swinging through a Jake Arrieta slider to cap a 12-pitch at-bat.

Crawford missed the rest of the homestand, five games, and suited up for the opener at Dodger Stadium. In the 13th inning of a 14-inning Giants loss, reliever Chris Hatcher drilled Crawford on the left calf, badly bruising and discoloring the area.

Crawford missed three games. Played five. Didn’t feel right. Didn’t play right. Missed the next seven. He probably would have been fine if not for getting plunked on the calf, but favoring the calf put pressure on the oblique and aggravated it.

Crawford didn’t have his leg strength, and what’s a shortstop without his leg strength?

“I knew my body wasn’t feeling right, and I wasn’t playing well or helping the team with the way I was swinging,” said Crawford, who was 2-for-24 while playing hurt. “My range was a little more limited. At that point, I realized it was best to get both injuries taken care of.”

A stellar overall season for Crawford, who was rewarded as possibly the majors’ best shortstop with his first All-Star appearance, isn’t ending how he imagined, thanks to the dents in his team and body. His batting average, in the .290s in June, has dropped 10 points since the injuries to .255, not much better than his past three seasons: .248, .248, .246.

But that doesn’t tell the whole story. Crawford has set career highs, by large margins in some cases, in home runs (19), RBIs (77), doubles (30), runs (58) and total bases (212). He posted huge spikes in slugging percentage (.463), OPS (.778) and WAR (5.4), topping big-league shortstops in all three categories.

He has 12 errors, down from 21 last season.

“For the most part, I stayed with a pretty consistent approach,” Crawford said. “Even when guys were changing the way they were pitching me, I stayed with the approach and stayed up the middle a lot better.”

Crawford’s replacement, .180-hitting Ehire Adrianza, was sketchy defensively at first but has improved his play of late. He’s 6-for-19 with six RBIs in his past six games, but that didn’t come until the Giants fell 8½ games back in the standings.

It hasn’t been the same without Crawford, who provides a calming effect when pitchers and fellow infielders glance his way and feed off an expression and body language depicting cool and and casual.

What will Crawford try to accomplish the rest of the way?

“Win games, really. That’s first of all,” he said.

Second of all? Crawford smiled. “Maybe get one more,” he said, referring to a 20-homer season, which never was expected for the shortstop who used to be all-glove, no-hit and now is, well, irreplaceable.