Sean Manaea is certainly making a case to make the A's opening day roster when he turns 24 years old next season. 

On Tuesday, the 6-foot-5 left-hander was named the Arizona Fall League Pitcher of the Week. He only made one start, but it was clearly his best one at the AFL. 

In five innings pitched, Manaea struck out nine -- the most by any pitcher for a single outing this year at the AFL -- and only walked one. He also only allowed two hits and one earned run. 

Less than two weeks ago, Manaea was making a name for himself in the Fall Stars Game.

There Manaea threw two scoreless innings while striking out four and only walking one batter. He didn't surrender one hit, tossing 31 pitches and 20 strikes. 

Manaea was the headliner in a trade that sent Ben Zobrist from the A's to the Royals before the 2015 trade deadline. 

Last season, between four teams in the minors, Manaea went 7-1 with a 2.66 ERA and struck out 90 batters in 74.1 innings pitched. 

Manaea is ranked as the A's No. 3 prospect by