Absent star performances, Giants struggle

The defending world champs are taking a tumble of late. Between a 10-17 June and an MLB-low 16 wins since May 14 (tied with the Brewers), the San Francisco Giants are falling fast at a time when the Dodgers, Diamondbacks and perhaps even the Padres all seem to have gotten their acts together.

There’s no magic bullet to sift out of the data to suggest that they’re going to turn themselves around all that easily. It isn’t like the pen’s a problem or they’ve been unlucky in tight games. No, the Giants’ real problem is a more demoralizing combination of two factors that aren’t easily fixed.

First, there’s the flat-out poor performance from the rotation that was half of their formula for success (Buster Posey + Pitching = Profit). The Giants’ road ERA of 5.30 ranks 28th in the league. Matt Cain’s five straight quality starts suggests that at least he might be getting back to pitching like himself, but with Ryan Vogelsong down and Tim Lincecum and Barry Zito now reliably unreliable, it’s hard to see how the Giants get back to boasting one of baseball’s best rotations. Moving The Freak to the pen might get better value out of him, but it doesn’t answer whom they would get innings and winnable ballgames from for the next half-season.

That might suggest that lefty Mike Kickham, Monday’s starter, could be part of the cure to what ails them, but Kickham is in danger of being a symptom of the Giants’ other problem: depth.

That’s because once you get past the bold-print signal successes by Giants player development, guys like Madison Bumgarner and Posey, you don’t find a lot of homegrown goodness ready to step in once their veterans struggle or break down. Fortunate as they were to run into a scrap-heap find like Vogelsong, without him the Giants are learning how the other half lives when it comes to conjuring up quality pitching -- and not the half that can call up a Gerrit Cole or Michael Wacha or Tyler Skaggs in their moments of need. Kickham has a nice arm and he rates well within the Giants organization. But that isn’t the same thing as having a top-shelf prospect who is going to help you stay in a game or in a race, or fix your organization.

That lack of depth also crops up when you take note of the rest of the roster. They’ve had to do without third baseman Pablo Sandoval for weeks at a time, and center fielder Angel Pagan might be gone until September.

While you might fret that the recent absence of Kung Fu Panda is the problem, you’d be wrong, because this goes beyond him. The Giants went 8-11 in the games Sandoval has had to miss so far, scoring just 4.06 runs per game -- which isn’t very different from the 4.11 runs they’re averaging on the year. They’re just a .500 team with Sandoval, and a little less than that without him. Maybe some of that can be blamed on bloat; of expectations of what Panda’s capable of, or of the Panda himself. But much like the rotation, the problem has been less one of absence and more one of flat-out mediocrity or worse when Sandoval is playing.

On the other hand, if you really want to play this “How bad are they without Player X?” game, the missing man you really want to talk about might be Pagan. The Giants are 12-20 since Pagan went on the DL, and they’re scoring just 3.5 runs per game in that span. Maybe that would fly when the Giants had the best rotation in baseball, but that’s no longer the case. Pagan might not be Rickey Henderson or Tim Raines at the top of the order, but on a roster already winging it with waiver-bait journeymen like Gregor Blanco and Andres Torres to cover left field, losing Pagan was a hit the Giants’ offense could ill afford. What runs the Giants automatically pick up on the competition because of Posey behind the plate, they’ve handed back because of a low-powered outfield beyond Hunter Pence.

Keep in mind, the Giants have more than a few guys hitting about as well as you might have expected from them coming into the year. Pence is putting up an .809 OPS; his career mark is .813. Marco Scutaro might have come down from last year’s epic stretch performance, but he’s delivering his highest OPS since the 2009 campaign that represented a career best at the time. Brandon Belt isn’t hitting much less than projected. Heck, even Brandon Crawford is having a career year by his own (admittedly modest) standards. These Giants are doing about as well as you could reasonably expect -- and it isn’t enough to carry a club while the stars struggle.

Last week’s revelation that Pagan needed surgery that will keep him out until at least early September doesn’t help matters, because the farm system doesn’t have anything close to resembling a ready alternative.

This is not to pick on the Giants’ farm system. Posey and Bumgarner are the sort of studs any player-development team would want to hang its hats on. It isn’t like they’re already out of an NL West race that any of the five teams could yet win. But without ready-now talent to call up or already-rostered veterans worth turning to, the Giants’ bid depends on their stars to step up. Posey already is, Bumgarner is and Cain seems back, too.

But as the deadline approaches, the question should be less whether Brian Sabean pulls a deadline-day rabbit or two out of his hat, but whether even that would give the Giants enough to overcome a roster that isn’t deep enough to sustain getting anything less than excellence from any of their stars.

Christina Kahrl covers baseball for ESPN.com. You can follow her on Twitter.