SCOTTSDALE, Ariz. -- Interest in an exhibition game tends to wane after a few innings, when the regulars or starters leave and the diamond is filled with guys wearing No. 86.

That won't be the case with the Giants this spring.

Seeking to establish both their lineup and their depth while developing a handful of intriguing prospects, the Giants will bear watching for all nine innings of each game, beginning with Saturday's Cactus League opener against Arizona at Scottsdale Stadium.

Maybe a substitution will be just a substitution. Or maybe it'll provide insight into an impending personnel move or the team's pecking order. Or it'll showcase a Minor Leaguer who could arrive at AT&T Park later this year.

Among manager Bruce Bochy's maneuvers to watch, many will revolve around three key performers -- catcher Buster Posey, second baseman Freddy Sanchez and closer Brian Wilson -- who might not play until the season's second week.

The dates of the spring debuts for Posey, Sanchez and Wilson will be duly noted and highly anticipated, since the Giants hope to have each of them ready for the April 6 regular-season opener at Arizona.

"I don't think it'll be long before I get in some games here," said Posey, who's recovering from extensive left leg injuries sustained in a home-plate collision last May 25.

With Posey certain to need rest from the rigors of catching to relieve his leg of wear and tear, competition for the backup spot acquires a much higher profile. Chris Stewart, who's in the mix for the job with Eli Whiteside and Hector Sanchez, will start Saturday as Tim Lincecum's batterymate.

Mike Fontenot will fill in for Freddy Sanchez on Saturday, launching what could be a three-man race with Ryan Theriot and Emmanuel Burriss for two backup middle-infield spots. All could make the Opening Day roster, with one of them starting, if Sanchez needs more time to heal his dislocated right shoulder.

The last spot in the bullpen annually prompts a spirited pursuit, but the Giants could have two openings if Wilson's balky elbow forces him to begin the season on the disabled list. Right-handers Clay Hensley and Steve Edlefsen and left-hander Dan Runzler are among the contenders to complete the relief corps.

But Wilson firmly believes he'll open the regular season on the active roster.

"I should get roughly 10 or 11 innings in spring," Wilson estimated. "That's good enough."

Another Giant saddled with questionable health is right-hander Ryan Vogelsong, the No. 4 starter who has been idled with back spasms since the start of Spring Training. The Giants are optimistic that Vogelsong will be ready for the start of the season, but the possibility that he'll need more time to get his arm in shape gives hope to left-handers Eric Surkamp and Brian Burres.

The Giants aren't just concerned about players on the mend and who might replace them. They want to learn more about numerous able-bodied performers:

Can Aubrey Huff, who'll start at first base against Arizona, demonstrate that he's poised to regain his 2010 form? Or will Brandon Belt or Brett Pill supplant him?

The Giants want Pill on the Opening Day roster, even as a reserve, since they're short on right-handed batters. How many different positions might he play (third base and left field are possibilities) to enhance his versatility?

The outfield trio of Melky Cabrera in left, Angel Pagan in center and Nate Schierholtz in right will start together for the first time Saturday. How will they mesh, and can Pagan and Cabrera thrive as a 1-2 combination at the top of the order?

Everybody knows that shortstop Brandon Crawford is a Gold Glove-caliber defender; can he hit proficiently enough to cement his status as a likely regular?

Can non-roster outfielder Gregor Blanco be another Andres Torres? How close are prospects such as reliever Heath Hembree and center fielder Gary Brown to the Major Leagues?

And, of course, can third baseman Pablo Sandoval function at his weight -- whatever that weight may be?

Fans won't have to wait long to see the first spring telecast involving the Giants on MLB.TV. It's scheduled for Monday, when San Francisco will entertain Milwaukee at 6:35 p.m. PT.