SAN FRANCISCO -- When Tim Lincecum leaves his scheduled start Thursday night at AT&T Park, nobody will know what he's striding toward. The uncertainty perplexes many people in the Bay Area.

Lincecum is bound for free agency, with his two-year, $40.5 million contract set to expire. He almost surely won't command such a lucrative deal on the open market, not after posting a 20-29 record with a 4.80 ERA since the start of the 2012 season.

Yet the possibility exists that Lincecum's upcoming start against the Los Angeles Dodgers will be his last in a Giants uniform.

That tortures legions of Giants fans who care more about emotion than economics. They yearn for Lincecum to stay and continue the marriage that has been an eventful and mostly happy one since he ascended to the Major Leagues in 2007. Lincecum hastened the Giants' rise from mediocrity while winning National League Cy Young Awards in 2008-09. He excelled in the 2010 and '12 postseasons to help the Giants win the World Series both times.

At the outset of Lincecum's career, fans marveled at how a 5-foot-11, 160-pounder could throw fastballs exceeding 95 mph. They reveled in his boyish features, carefree behavior and impossibly long stride. Though Lincecum's velocity has diminished, his attempts to adjust his pitching style -- highlighted by his July 13 no-hitter at San Diego -- suggest that magic remains alive in his right arm.

"The city hasn't loved an athlete like this since Joe Montana," said Brian Murphy, who co-hosts a popular morning sports talk show with Paul McCaffrey on KNBR-AM, the Giants' flagship station. "That includes Barry Bonds and Steve Young, and that includes Buster Posey and Matt Cain and Madison Bumgarner. He has a charisma and style about him, and I think the idea of the Giants without him is pretty daunting to a lot of fans. It would hurt a lot. They would be a lesser team and a lesser franchise to root for. I think a lot of fans are in sort of denial about it. I think you have your harder-edged, stats-based fan who says, 'Look at his numbers -- he's a No. 4 starter.' But I think there are more fans who remember the great times who are not emotionally prepared to see him go."

The 29-year-old appreciates his prominent place in the fans' hearts.

"All the mistakes I've made on and off the field -- they still love me despite that," said Lincecum, who was charged with misdemeanor marijuana possession after the 2009 season and blurted a profanity on live television during the Giants' on-field celebration of their 2010 NL West title. "You can feel that, and you don't feel like you're judged."

Lincecum reiterated his desire to remain a Giant, though he knows he must address business.

"I have to see what's on the table before I dismiss anything," he said.

Baseball's Collective Bargaining Agreement allows the Giants to make a one-year qualifying offer to Lincecum, which they will likely do. The figure attached to that offer, which is the average of the top 125 salaries from the previous season, probably will reach $14 million. If another team signs Lincecum, the qualifying offer will enable the Giants to gain a compensatory top Draft pick from that club.

Though that could limit interest in Lincecum, insiders believe he'll spurn the qualifying offer (he'd still be eligible to sign with the Giants in that event) in the expectation that he'll command at least a handful of multiyear bids with higher average annual values.

For now, Lincecum is still a Giant. MLB.com caught up with a representative sampling of ballplayers, mostly teammates past and present, to trace his career path. This story starts on the morning of Feb. 16, 2007, at Spring Training camp in Scottsdale, Ariz., where a handful of veteran pitchers delayed reporting for their next drill to watch the heralded Lincecum throw off a bullpen mound for the first time. Then, as now, Lincecum "wrapped" the ball around his right thigh as he rocked back to throw each pitch.

Barry Zito, Giants left-hander: "You just don't see that kind of delivery. Well, you do, but it's an old-school kind of thing. It was refreshing, at least for me, to see a guy who had a very unorthodox style but had a lot of success. It just shows that there are a hundred different ways to deliver a baseball. It's pretty cool, you know?"

Kevin Frandsen, Giants infielder, 2006-09: "I've never seen more guys in the Minor Leagues baffled by one guy. Hitters were ecstatic for a checked swing back to the pitcher's mound or just putting the ball in play off him."

Randy Winn, Giants center fielder, 2005-09: "I remember being in the kitchen about 30 minutes before a game in Colorado when he was a rookie, and he didn't have his uniform top on yet, and he was kind of singing to himself and warming up a Philly cheesesteak. I remember thinking, 'Do I say something to that kid?' Because most starters would be on the field, stretching and getting ready. That was kind of like the first time I saw 'The Freak.' And he went out and pitched great."

Brad Hennessey, Giants right-hander, 2004-08: "He was like a cat that could wake up and run. Timmy could wake up and throw hard. He'd throw nine pitches and was ready to go."

Bengie Molina, Giants catcher, 2007-10: "I couldn't believe what I saw. I was like, 'Wow, where is this kid coming from?' I was really, really impressed with the way he threw the fastball, the changeup, the curveball. I had never seen a kid like that coming up. I had always seen good pitchers, but this was a phenom. This was a kid who threw 100 [mph] with a great breaking ball and a great changeup. Sure enough, look at how he did."

Adrian Gonzalez, Dodgers first baseman, .200 lifetime hitter (10-for-50) off Lincecum: "He'd kind of throw that fastball at left-handed hitters and let it run back and catch a corner, then he'd follow with that changeup right behind it. If you wanted to hit a fastball, you had to kind of 'cheat' to it. Then if you cheated a little bit to it, you were out in front of the changeup. So that made him difficult to square up."

Zito: "He has such a loose delivery, real explosive. The way the ball comes out of his hand is so deceptive, because there's a lot of freedom in his delivery, and that leads to hitters not being able to recognize pitches."

Molina: "When I was catching, what I heard most often was, 'I can't see the ball. I can't pick it up.' It wasn't from the shadows. It was because of his weird motion and his delivery. He hides the ball well. It comes out of nowhere."

Javier Lopez, Giants left-hander: "One thing I've noticed is his ability to add pitches and be able to use them. Whether it be a new grip on a changeup, he can make that thing operational in a couple of hours. Other guys, it takes them months to figure it out."

Pablo Sandoval, Giants third baseman: "I love playing behind him, because if you make a play, he's the first guy waiting for you to give you a high five."

Zito: "He's a great presence in the clubhouse. He's always 'up.' Whether he's singing or dancing around, he's such a likable guy. Regardless of what his performance has been through the years, he's been that same kind of guy. It's good for older guys to see; it's good for younger guys to see."

Frandsen: "He didn't migrate to one guy in the clubhouse. He migrated to everyone. He hung out with everyone. He got along with everyone. ... I hadn't seen him for two years, yet the biggest hug I got was from him."

Lincecum: "This is my family, my family away from my family. It's always been my sports teams, and that's even when I was growing up. And it's the same way here."

Murphy: "Everything about him endeared him to the fan base. It was about style, it was about his look and his staggering performance in bringing that first World Series to the city. When Paulie Mac and I did FanFest in 2009 and had Timmy on stage, it was like the Beatles landing in New York City at JFK Airport in 1964. And that was before the World Series."

Hunter Pence, Giants right fielder: "He has that aura about him, that aura of greatness. I think beyond what he does on the field, he lifts the team up with how special he is and who he is. I would say he's one of the biggest fan sensations there is. That's why he's 'The Freak.' It's definitely worth the price of admission to watch him pitch."

Frandsen: "I think the crazy thing is his rock-star image. Where he went, people's mouths dropped. Every time. And you know how quiet he is. He wasn't looking for that. He'd put his hood up and he'd put his beanie on ... That was the craziest thing -- to see how much a guy who tried not to get attention got attention."

Chris Stewart, Giants catcher, 2011: "The word I like to use for him is 'bulldog.' He's gritty in any situation. He's going to bear down and bring his best at you. It didn't matter the situation; he was going to give you everything he's got. I remember those classic [Clayton] Kershaw-Lincecum matchups. They had quite a few the year I was there. Both guys going out and giving their all. They were 2-1, 1-0 games pretty much the entire time. That just goes to show how fearsome a competitor he is. He didn't necessarily have his best stuff each and every time, but he'd give you his best."

Aaron Rowand, Giants center fielder, 2008-11: "He hated to lose at anything. That's something that you really don't teach people. You're either born with it or you don't have it. Timmy had a way of rising to the occasion, whether we were playing the Dodgers or in San Diego, where we never played well. Give him a reason to get up for a game, and he got up for a game."

Winn: "He'd be happy-go-lucky Timmy, but as soon as he stepped on the mound, he transformed into this competitor. He didn't like the people he played against when he was on the mound."

Sandoval: "He fights every start. You see him working hard, working on his mechanics. I love that, when I see my teammates working hard to get better. I never lost my faith in Timmy."

Rowand, on the Giants' Game 5 clincher in the 2010 World Series: "I had the best seat in the house in center field. Timmy didn't miss a spot. Not only did he hit spots with his fastball, but he was throwing his changeup, breaking ball and slider, and everything was on a corner. I remember thinking to myself at about the fifth or sixth inning, 'I haven't seen him miss over the fat part of the plate with any pitch.' "

Pence, on Lincecum's no-hitter: "The thing I remember most is how many pitches he threw (148). There's no one else, I don't think, who can throw that many pitches, be that strong and not get hurt. He's an absolute horse."

Murphy: "Timmy helped change San Francisco from a 49ers town to a Giants town. That's arguable, and the 49ers' going to the Super Bowl last year certainly brought back a lot of the 49ers vibe. But Paulie and I often comment to each other, we still see more Giants gear than 49ers gear. And Timmy is on the shortest of lists of figures that helped change the town."

Lincecum: "It's been one memory after another. There were a number of guys who were here before me whose careers I got to see, and young guys who have come up and made names for themselves, and I've also been a part of that. My timing of coming up is pretty spot on."