If star power was any sort of measurement, the Oakland A's would have one of the worst starting rotations in baseball. They're currently using four rookies and a journeyman Aussie who was pitching for the illustrious Kia Tigers last season.
Star power isn't any sort of measurement, of course, and the A's have been proving that pretty consistently all season long. Their starters have a 3.72 ERA, which ranks fifth in baseball, and the club's rotation has posted a solid 3.49 ERA in September despite its sudden lack of depth and experience.
Much of the credit is owed to rookie righty Jarrod Parker. He's quietly been one of the most effective pitchers in the American League for virtually the entire season, but he's kicked things into an extra gear in the season's final month. He's pitching like a true ace these days.
Parker resurfaced in my weekly AL Rookie of the Year rankings a couple weeks ago, and he's earned the right to keep moving on up in this week's rankings. Scroll ahead to see where he and the other top candidates stand with a week to go (!) in the regular season.
Note: Stats are current as of the start of play on Wednesday, September 26, and they come from Baseball-Reference.com unless otherwise noted.