Rather, he was on the disabled list, where he spent a couple of weeks nursing a stress reaction near his left scapula.
Then, Cahill was found on the roster of Triple-A Sacramento, where he made two starts before being called upon by the big boys in Oakland -- only to fill in for the injured Brett Anderson.
Now, less than four months later, he's on the All-Star roster.
The 22-year-old Cahill, in just his second big league season, was officially selected by American League manager Joe Girardi on Sunday as the A's lone representative for this year's Midsummer Classic in Anaheim on July 13.
"I'm real happy for him," said manager Bob Geren, who was appointed by Girardi to the coaching staff last month. "I was hoping we'd get more than one, but if you had to pick just one, what he's done in the last month or six weeks, he's definitely worthy of being honored as an All-Star. He's been as good as any pitcher in the American League, so he deserves to be on the team with the best in the league."
Per usual, the always soft-spoken Cahill's words came in a humble form, his appreciativeness for the honor bestowed upon him undeniable.
"Pretty unbelievable," he said shortly after learning the news. "Just thinking where I was just a couple months ago on the disabled list with my left shoulder, then with Sacramento ... I didn't even have a good first start when I came back."
It was far from "good," in fact. Cahill got knocked around in Toronto on April 30 for seven hits, three of them home runs, and six earned runs in just five innings. Since then, though, he's surrendered more than three earned runs just once in 12 starts and owns an 8-2 record with a 2.74 ERA, good for sixth in the AL.
"At the beginning of the year, I never even dreamed I'd be in this situation right now," he said. "I think it's just a little extra edge having been hurt and then being sent down, so it's just a great feeling.
"I think the biggest thing is just confidence that I learned last year, not just knowing the hitters but knowing how to win, plus adding the new breaking ball and locating all my pitches."
The All-Star Game will be televised nationally by FOX and around the world by Major League Baseball International beginning at 5 p.m. PT. ESPN Radio will provide exclusive national radio play-by-play, while MLB.com will offer extensive online coverage.
Fans, having already decided the starters and this week the final player on each team, once again will have the opportunity to participate in the official voting for the Ted Williams Most Valuable Player presented by Chevy via the 2010 All-Star Game MVP Vote Sponsored by Sprint on MLB.com during the All-Star Game.
This marks the ninth consecutive year the A's have sent at least one pitcher to the All-Star Game, where they haven't had a position player invited since catcher Ramon Hernandez was selected along with pitchers Keith Foulke, Mark Mulder and Barry Zito in 2003.
Mulder was again selected, next to Tim Hudson, in 2004, which marks the last time Oakland has had more than one player represented at baseball's storied game. However, there's still a chance Cahill could be joined by 2009 All-Star reliever Andrew Bailey, who -- along with catcher Kurt Suzuki -- was highly touted by Geren leading up to Sunday's announcement.
Cahill is scheduled to pitch the final Sunday before the All-Star Break, which would make him ineligible for the AL active roster. If he does indeed start, the alternate appointed in his place must be a pitcher.
"I thought he was easily going to make it again," Cahill said of Bailey, "and he still has a chance.
"I know Bailey's had a great year again, so I was kind of surprised it was me and not him, but I think we have a lot of deserving guys on this team, and this year I was lucky enough to go."
Geren echoed his pitcher's sentiments, saying he'll soon speak to Girardi -- the two skippers meet in Oakland beginning Monday for a three-game set -- and make a final push for his closer, who owns 17 saves and a 1.59 ERA. Cahill, meanwhile, doesn't mind watching as an inactive player from the sidelines, where Bailey sat last year when not afforded the chance to get in the game.
"Looking at the list of all the arms," he said, "there's probably a slim chance I'd get to pitch, anyways. There's guys with so much experience, so that's not a big thing. I think the biggest thing is just being selected and being able to participate in all the activities."
Suzuki, meanwhile, seemed to be another logical choice to represent the A's in Anaheim given his steady production and highly regarded work with the club's young pitching staff. The same notion arose last year, but Cahill doesn't think it will be too long before his battery mate finally gets his shot behind the plate, where fan-voted starter Joe Mauer of the Twins will be joined by Boston's Victor Martinez (DL, inactive) and Toronto's John Buck this year.
"I think he does so many things right that a lot of guys don't see when you're not watching him every day," Cahill said. "Without him, I don't think our team would be anywhere close to where it is. I think he's kind of underrated, has a good bat, but I think he'll have plenty more opportunities in the years to come. There's no doubt in my mind he'll make the team quite a bit."
Cahill, selected in the second round of the 2006 First-Year Player Draft, quickly climbed the ranks through Oakland's Minor League system, in which he was named the club's Organizational Pitcher of the Year in 2007 and 2008. He also was selected to the All-Star Futures Game, as well as the Summer Olympics in Beijing, China, in 2008.
None of those experiences quite match this one, though. In fact, Cahill likened the All-Star opportunity with only that of being told he made the big league roster following Spring Training last year. Even more thrilling for the youngster is knowing he'll be brushing shoulders with baseball's best just miles from where he grew up in Oceanside, Calif.
"I can't think of a better place to have it," he said. "I was just going to fly home for the break. I probably would have flown into John Wayne [Airport], anyways."
Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.