Mike Fiers threw Oakland's most-recent no-hitter on May 7 last season against Cincinnati.
Acker posted a 3.51 earned-run average this season for OU.
The Athletics drafted OU outfielder and quarterback Kyler Murray ninth overall in 2018, but he opted to stick with football after winning the Heisman Trophy and going No. 1 overall in the 2019 NFL Draft to the Arizona Cardinals.
