Chicago Cubs starting pitcher Trevor Williams (32) delivers a pitch against the Pittsburgh Pirates during the first inning at PNC Park.  Charles LeClaire-USA TODAY Sports

Cubs hurler Trevor Williams will be out indefinitely after undergoing an emergency appendectomy, per Jared Wyllus of the Chicago Sun-Times. Williams was originally slated to start Monday’s game against the Padres.

It’s looking like Keegan Thompson will step in for a spot start. The 26-year-old made his first career start in the second game of a doubleheader against the vaunted Dodgers back on May 4, tossing 3 2/3 scoreless innings. Thompson has yet to surrender an earned run in his young career with 15 scoreless innings over his first nine appearances. He’s done a tremendous job of keeping the ball on the ground so far with a 58.3 percent groundball rate, though that’s not a tendency he displayed as a minor leaguer.

As for Williams, the situation might seem more dire than it is, given the “indefinite” designation of his injury status. Likely, this is simply a matter of wait-and-see, assuming there were no further complications to the surgery.

They will need to replace his production in the meantime. Williams hasn’t exactly been a revelation since joining the rotation from the Pirates – 5.36 ERA/4.76 FIP while averaging less than five innings per start – but if nothing else, he’s striking out batters at a career-best rate of 24.9%. He’s also walking more batters than usual with a 10.2 percent walk rate. To his credit, Williams has allowed two or less earned runs in seven of his 10 starts, and he’s coming off his best outing of the year, a six-inning, one-earned-run effort against his former club in Pittsburgh.

More must-reads:

TODAY'S BEST
Cubs designate lefty reliever for assignment
Two-time Super Bowl champ signs with AFC contender
Stars center matches Gretzky feat as Dallas pushes Avalanche to brink
Gritty young Thunder take down veteran Mavericks in Game 4
Cubs acquiring veteran reliever from Mariners
Top-five NBA Draft prospect suffers scary non-contact injury
Hurricanes stay alive with third-period outburst vs. Rangers
Jaylen Brown's big three-pointer gives Celtics 3-1 lead over Cavs
Avalanche star placed in player assistance program
Mercury announce devastating injury on eve of WNBA season
Randy Moss' son makes major football announcement
Reds place key outfielder on injured list with broken thumb
Tom Brady's broadcasting debut set for Week 1 of NFL season
Struggling Cubs reliever placed on injured list 
Report: Justin Fields had ‘toxic' relationship with ex-Bears QB
Extension makes Lions QB Jared Goff one of NFL's highest-paid players
Kentucky's Reed Sheppard displays excellent skills at NBA Draft Combine
Knicks big man undergoes another ankle surgery
Flames CEO stepping down, transitioning to advisory role
Oilers star seemingly dismisses Arturs Silovs' performance in Game 3