That was in 2006. Now King Felix is one of the favorites to win the 2009 American League Cy Young Award.
Granted, Hernandez made his debut at 19 years old (in 2005). Cahill is 21 -- still a pup, but at least allowed to legally buy a beer. And the two right-handers aren't exactly stylistic carbon copies.
Hernandez is a power pitcher with strong secondary stuff. Cahill kills with craftiness when he's at his best, baffling batters with a darting sinker, and he rarely roams into the mid- to high-90s neighborhood in which Felix's fastball resides.
But talent is talent. You saw it when Hernandez was breaking in, and you see it when Cahill takes the mound, results be damned.
"Oh, his talent level is tremendous," said Seattle skipper Don Wakamatsu, whose club was dominated in Cahill's second start of the season. "He's the real deal."
The results on Tuesday were not tremendous. Cahill couldn't get out of the fifth inning and allowed six runs on eight hits and two walks over 4 2/3 innings of a 6-4 loss in the opener of a three-game series at Safeco Field.
A tough night, to be sure. But not so tough to obscure the work he's done all year, particularly over the past month.
Cahill had gone 4-0 with a 2.28 ERA over his previous five starts.
"What we've seen is improvement in all areas," said A's pitching coach Curt Young. "And what he should be the most proud of is the kind of confidence he's been taking out to the mound with him. That's a key for any pitcher, and he's really done a nice job of taking that out there these past five or six weeks.
"He's had some ups and downs, and there's always room for improvement even after a great game or a great year. But Trevor knows what he has to do, and he's on his way."
Hernandez is already there. In his penultimate start of the season, he improved to 18-5 with a 2.48 ERA while holding Oakland to two runs over 7 2/3 innings of seven-hit work.
It wasn't always pretty, though. Hernandez walked four and hit two batters, and the A's put plenty of pressure on him to be at his best.
"His command wasn't quite what we've seen in the past," A's manager Bob Geren said of Hernandez, who threw 120 pitches. "He's one of the premier pitchers in the game and we had runners on base in almost every inning. But he made pretty good pitches when he needed to."
The Mariners opened the scoring in the second after Cahill walked Ken Griffey Jr., who moved to third on a double by Adrian Beltre and scored on a groundout. Oakland evened the score in the fourth, with Jack Cust drawing a one-out walk, taking second on a wild pitch, moving to third on a groundout and scoring on a single by Mark Ellis.
Cahill, who'd already set the Oakland rookie record for home runs allowed, was done in by Griffey's three-run homer in the fifth. It preceded Franklin Gutierrez's sacrifice fly, was followed by an RBI double from Bill Hall and marked the 27th time this year that Cahill's been taken deep.
"Most of the homers Trevor has allowed," Young said, "have been on sinkers in fastball counts that he left up over the plate."
Cahill didn't disagree, responding to a question about what he's learned this year by first saying, "How important it is to stay down in the strike zone."
That was the primary problem Tuesday.
"I was leaving a lot of balls up all night," Cahill said. "My sinker wasn't really moving. ... Sooner or later, that's going to catch up with you."
The A's finally pushed Hernandez offstage with a chippy little rally in the eighth that featured singles by Travis Buck and Kurt Suzuki, a right-side grounder and a sacrifice fly by Daric Barton.
Hernandez left to a standing ovation and tipped his cap in acknowledgment after plunking Ellis and walking Eric Patterson to load the bases with two out, but righty Mark Lowe came on to end the threat by striking out Cliff Pennington.
Suzuki's two-run single with one out in the ninth added some drama to the proceedings, keeping alive Oakland's hope for a 6-0 finish that would allow them to finish at .500 for the year, but that hope died when Cust popped out and Barton flew out to end the game.
"The second half of the year has been outstanding," Geren said. "We have a lot of things to be pleased with going into the offseason ... and Trevor's development -- the way he's finished the year healthy, not missing any starts, pitching well -- is definitely one of them."