The dawn of 2009, however, brought an unexpected text message that offered Crosby the opportunity of a lifetime. Thanks to that message, he's as upbeat as ever.
"I can't wait for Spring Training to start," Crosby told MLB.com by phone from Southern California on Thursday evening. "I'm really, really excited."
Given what Crosby has gone through this winter, it's a fairly remarkable sentiment to express. But that's how much working with Mark McGwire, one of Crosby's childhood heroes, has meant to the star-crossed 2004 American League Rookie of the Year.
McGwire is ill-fated himself these days, the legitimacy of his illustrious career as one of the game's most feared power hitters called into question by persistent speculation regarding performance-enhancing drugs. He was in the news again Thursday, when it was reported that his younger brother Jay said in a book proposal that the former slugger began taking steroids in 1994 and that he had personally injected Mark with performance-enhancing drugs.
But "Big Mac" has the undying respect and admiration of Crosby, who grew up loving all things green and gold. And as a direct result of a text message that came from new teammate Matt Holliday, Crosby now has McGwire's ear.
Three times a week since the calendar flipped to January, Holliday and Crosby have been meeting McGwire at the University of California-Irvine and hitting in the cage under the watchful eye of one of the greatest A's of all-time.
"It's a really cool thing," said Crosby, whose father was a scout for the A's. "It's a little bit of a trip being able to pick his brain like this. I mean, I had a poster of him on my wall as a kid.
"If you'd have told me 20 years ago that I'd be learning about hitting from Mark McGwire, I would have fainted."
Laughing at the memory of how nervous he was upon first meeting McGwire at UCI, Crosby said he did, in fact, nearly fall over.
"The first thing he said once we got into the cage was, 'Let's take a look at your [batting] stance.' So I get into my stance, and he pushes me," Crosby recalled. "I didn't fall down, but I fell backward, because I wasn't balanced. And that was his point. The first key to hitting is being balanced, and I wasn't."
Another thing Crosby wasn't this winter, it seemed, was wanted.
After unsuccessfully trying to replace him via their very public pursuit of free agent Rafael Furcal, the A's tried to give him away by placing him on unconditional waivers.
Scared off by his 2009 salary ($5.5 million), his injury history (six trips to the disabled list in four years), his lack of consistent production (his .237 batting average in 2008 was his highest since 2005), or some combination of the three, nobody took the bait.
Crosby, who heard nothing from the A's front office while all of this was going on, was in the worst kind of limbo.
"It's not the funnest thing in the world to go through, that's for sure," Crosby conceded.
Holliday's text didn't change Crosby's situation, but it led him to McGwire, who changed Crosby's mechanics.
"I don't know what he looked like before, but from the first day I saw when he hit with us to now ... he's pretty drastically different," Holliday said Thursday, while making his first Bay Area appearance since the A's acquired him in a November trade with the Rockies.
"The ball's coming off his bat real well, and he looks great. I don't know Bobby career-wise, so I can't say what he used to look like, but he looks great to me. I think Mark's helped him a lot, so I'm excited for him.
"I think he's going to have a good season."
While trying to explain the changes he'd made in both his stance and swing, Crosby essentially said his approach has been McGwire-itized. The stance now features a version of McGwire's distinctive crouch, the swing resembling the compact stoke that helped McGwire hit 583 home runs.
"It's a little more in my legs, and I'm taking a direct path to the ball. In the past, I took a longer route," Crosby said. "It's a lot shorter, a lot quicker. It feels awesome."
One of the greatest benefits of the shorter stroke, Crosby suggested, is that he doesn't have to set up as far away from the plate as he used to.
"There's more of a comfort level to be on the plate now," he explained. "Mac always had such a short stoke that he could get to that inside pitch and still crush it. Now I can get to that inside pitch, too, instead of cheating on it like I used to. And when I was off the plate to cheat on the inside pitch, I was so far off I had to dive to pitches off the plate."
Said Holliday, "When you're talking the mechanics of hitting, Mark's fantastic."
When the subject shifted from his stance to his standing with the A's, Crosby insisted that he wasn't bitter and pledged to be nothing short of a happy camper when he reports to Phoenix next month.
"That's the business part of it, and I understand that," he said. "I haven't had the best couple of years, and I know it's not personal. This kind of thing happens to a lot of guys; I've seen it. ... It's definitely been a weird offseason, but I've still done my work, and I'm going to come in with the right attitude."
Teammate Travis Buck, who joined Holliday at an A's media function at the Oakland Coliseum on Thursday, said he admires the way Crosby has handled himself this offseason and wondered if he'd have been able to handle it as well.
"You see a guy go through something like that and think, 'How would I respond to that?'" Buck said. "But Bobby -- he and Jason Kendall took me under their wing when I was a rookie -- is an unbelievable guy and an unbelievable teammate. Knowing what kind of competitor he is and what kind of person he is, I know he'll succeed wherever he is.
"He's a very intense, competitive guy ... I guarantee that he's going to come in with a big chip on his shoulder, and it wouldn't surprise me if he has a great year."
If he does, Crosby will owe much of his success to McGwire -- and Holliday, who Crosby had never met before he received the text.
"It basically said, 'Hey, this is Matt Holliday. I'm hitting with Mark McGwire. Do you want to join us?'" Crosby said. "I still haven't asked him how he got my phone number."
Suffice it to say that he doesn't really care, either. That Holliday reached out to him, Crosby said, speaks volumes about him as a person and as a teammate.
"He's just a great guy," Crosby said. "I came back home after hitting with him the first time and told my wife, 'I'll definitely get along with this guy.'"
Mychael Urban is a national writer for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.