PITTSBURGH -- Earlier this season, Chad Kuhl harnessed his high-octane arsenal and emerged as the Pirates' best pitcher for about six weeks. He'll have to wait, unfortunately, for his next chance to prove himself.
Kuhl on Wednesday underwent right elbow ulnar collateral ligament reconstruction surgery, more commonly known as Tommy John surgery. Dr. David Altchek performed the operation at the Hospital for Special Surgery in New York. Pitchers typically return to Major League competition 14 to 16 months after the surgery, so Kuhl will miss all of next season but could return in 2020.
Kuhl posted a message on Twitter saying he is "ready to tackle this next step" along with a photo of himself following the operation.

Kuhl last pitched on June 26, when he exited his start against the Mets at Citi Field after four innings due to what the Pirates called "right forearm discomfort." The Pirates' medical staff and Dr. Altchek both recommended that Kuhl's forearm strain be treated with conservative management, not surgery, so he was shut down from throwing for four weeks.
The Pirates transferred Kuhl to the 60-day disabled list on July 31. He began a throwing program last month and made it back to the mound for a bullpen session of only fastballs. But his forearm and elbow flared up when he attempted to use his offspeed pitches during a flat-ground throwing session in St. Louis, so Kuhl was sent to see Dr. Altchek again on Wednesday.
Kuhl was Pittsburgh's most effective starter from May 6-June 15, posting a 2.89 ERA in 46 2/3 innings over eight starts. Overall this season, he put up a 4.55 ERA and 1.44 WHIP in 16 outings. He owns a 4.37 ERA and 1.43 WHIP in 61 career starts over the last three years.
After reaching the Majors as a sinker/slider-heavy ground-ball artist, Kuhl last year saw his fastball touch 100 mph while introducing a high-spin curveball. It all started to come together earlier this season before he gave up eight runs in two innings vs. the D-backs on June 21, his second-to-last start of the year.
The Pirates have the rotation depth to withstand Kuhl's injury if it sidelines him for a significant amount of time next season. Nick Kingham filled in during the first month of Kuhl's absence, then Chris Archer effectively took over his spot in the rotation. Archer is set to return next season, along with Jameson Taillon, Trevor Williams, Joe Musgrove and Ivan Nova.
Kingham is also under club control, though he will be out of Minor League options next year and could land in the big league bullpen. The Pirates have also used Clay Holmes as a starter three times this year, and left-hander Steven Brault made five starts earlier this season. Mitch Keller, the Pirates' No. 1 prospect according to MLB Pipeline, advanced to Triple-A Indianapolis this year and should return there to begin next season.
Trainer's room
• The Pirates on Tuesday placed right fielder Gregory Polanco on the 10-day disabled list, a procedural move made retroactive to Saturday. Polanco is doing well a week after undergoing surgery to repair his dislocated left shoulder and torn labrum, director of sports medicine Todd Tomczyk said. Polanco's recovery is expected to take seven to nine months, and the first stages of that process will take place soon in Bradenton, Fla.
"He has a very long journey ahead of him, but he's very optimistic," Tomczyk said. "He's in a good mindset right now."
• Infielder Jungho Kang, working his way back from wrist surgery, had a handful of at-bats in a simulated game on Wednesday in Bradenton, Tomczyk said. The Pirates hope to get Kang into fall instructional league games, and they have not ruled out a return to the Majors before the end of the season.
• Catcher Elias Diaz (strained right hamstring) returned to the field as a pinch-hitter on Tuesday night and walked in his only plate appearance during the Pirates' 2-1 win over the Royals, his first game action since Aug. 31.