Cassevah, 24, was one of 17 players taken in the Major League phase of December's Rule 5 draft. He posted a 3.68 ERA, 5.5 K/9, and 4.5 BB/9 in 73.3 relief innings for the Angels' Double A club, allowing just two home runs. Baseball America ranked Cassevah 26th among A's prospects, praising his heavy 92-94 mph sinker but suggesting he has middle reliever upside given the control problems.
Given the $21MM spent on one-year deals, the A's fancy themselves contenders in the AL West. As such, it would've been difficult to keep Cassevah in the Majors all year.