Speaking to reporters about the rule change, Bumgarner offered a matter-of-fact response to not being able to step in the batter's box this season.
"Obviously my thoughts don't really matter on that deal," he said. I do what I'm told. I'll sit there and pitch and that's it for now. I think that's obviously where everybody wants the game to go so it is what it is."
Bumgarner became a four-time All-Star with the San Francisco Giants for his pitching prowess, but he developed into a legitimate power threat with the bat.
Since the 2012 season, Bumgarner has hit 19 home runs and has won two Silver Slugger awards. His power output in 2016 led to a petition for him to participate in the Home Run Derby, but the MLB Players Association nixed the idea.
"The players union doesn't want a pitcher taking a player's spot, and I don't think they were keen on the pitchers thing this year," then-Giants manager Bruce Bochy told reporters in June 2016.
Under the official rules for the 2020 season, the designated hitter will be used in the American and National Leagues to lower the potential risk of injuries for pitchers.
It is possible that Bumgarner could get some at-bats this year as a pinch hitter if Diamondbacks manager Torey Lovullo needs someone who can drive the ball into the gap or over the fence.