"I don't recall ever having as many guys having big months the same month," Antony said.
Buxton, ranked as the No. 19 overall prospect according to MLB.com, hit .392/.510/.684 with four homers, five doubles, three triples and nine stolen bases in 22 games at Class A Cedar Rapids in April.
The 19-year-old beat out fellow top prospect Miguel Sano, who batted .368/.435/.747 with a Minor League-leading nine homers and 24 RBIs in 25 games in April with Class A Advanced Fort Myers. Other top candidates were Adam Walker and Jorge Polanco of Class A Cedar Rapids .
"Sano -- when you hit home runs in that ballpark, in that league, with the big league Spring Training ballparks, that's impressive," Antony said. "Buxton walked more than he struck out -- that kind of discipline, and hitting the way he is. Adam Walker had 16 RBIs in a week. Jorge Polanco is hitting .350 at Cedar Rapids. Any of those guys would normally win it."
Baxendale, 22, was impressive at Fort Myers in April, going 4-0 with a 1.84 ERA in five starts. Baxendale, taken in the 10th round of last year's First-Year Player Draft, also struck out 25 and walked six in 29 1/3 innings.
He beat other candidates such as Steven Gruver and Tyler Duffey at Cedar Rapids and Alex Meyer at Double-A New Britain.
Rhett Bollinger is a reporter for MLB.com. Read his blog, Bollinger Beat, and follow him on Twitter @RhettBollinger. This story was not subject to the approval of Major League Baseball or its clubs.