Brewers reliever Corey Knebel has elected to undergo Tommy John surgery, he tells reporters including Tom Haudricourt of the Milwaukee Journal-Sentinel (Twitter link). The rehab process will take him out of action for all of the 2019 season and quite likely some of 2020 as well.

Knebel had been weighing the replacement of his right ulnar collateral ligament after speaking with multiple physicians. Evidently, it was less than a clear-cut decision, but he ultimately decided to bite the bullet rather than taking an uncertain rehab course that may only have delayed the inevitable.

The 27-year-old hurler had already agreed to a $5.125MM arbitration salary in his second season of eligibility. As a former Super Two qualifier, he’s eligible twice more. Whether the Brewers elect to tender him a contract next fall may depend upon how his rehab is progressing. Knebel would stand to earn a repeat of this season’s salary, which may be a bit of an expensive gamble. The presence of another season of arb eligibility certainly boosts the merits of a tender.

No matter how the future plays out, the reality at present is that the Brewers are down a key arm in the pen. Though he wasn’t as dominant last year as he had been in 2017, Kluber still ran up 55 1/3 innings of 3.58 ERA ball while recording an eye-popping 14.3 K/9 against 3.6 BB/9. Thankfully, the unit is still headlined by Josh Hader and Jeremy Jeffress (once he’s off the IL), but there’s little question it’s weakened from its ’18 levels.