HOUSTON -- Astros right-handed pitcher Lance McCullers underwent Tommy John surgery on his right elbow on Tuesday, the team announced. McCullers will miss the entire 2019 season, but he is expected to make a full recovery.
McCullers, 25, left his Aug. 4 start against the Dodgers at Dodger Stadium with right-elbow discomfort and was later diagnosed with a forearm strain, forcing him to miss six weeks. He came back to make three scoreless relief appearances in the final week of the regular season and pitched five more times in relief in the playoffs.

After the Astros were eliminated in five games by the Red Sox in the American League Championship Series, McCullers said he had been pitching through "some stuff," but wouldn't get into specifics.
"This wasn't a complete surprise to us," said Astros president of baseball operations and general manager Jeff Luhnow by phone from the GM Meetings in Carlsbad, Calif. "We knew there was a probability, possibility Lance was going to have his elbow injury taken care of surgically. All along, we've been planning for having to fill innings, not only for our free-agent starters who were with us last [season], but also the possibility that Lance may not be in the rotation."
The loss of McCullers is a huge blow to the Astros' pitching rotation plans for 2019. The team is likely to lose Dallas Keuchel in free agency and perhaps Charlie Morton to free agency or retirement. Justin Verlander and Gerrit Cole return for the final seasons of their contracts with the Astros next year, but the Astros will be in pursuit of starting pitching.

McCullers went 10-6 with a 3.86 ERA in 25 appearances (22 starts) last season, striking out 142 batters in 128 innings. He posted a 10-4 record in his first 19 starts prior to the All-Star break before suffering his elbow injury against the Dodgers. Luhnow said McCullers was showing no symptoms of his injury when he returned to the mound.
"That all being said, there was an injury to his elbow that was in there," he said. "Most pitchers have some sort of tear in their elbow and typically it's a matter of what the symptoms are, how big the tear is, which leads to a decision with the player or the medical staff as far as what the course of action is. We were very careful not to take any undue risk with Lance in terms of how we used him in the postseason, and we were all on the same page with our medical staff and him."
The No. 41 overall pick of the Astros in the 2012 MLB Draft, McCullers hasn't put together a full healthy season. He made 22 starts in his rookie season in 2015 and was limited to 14 starts in '16 with a sore shoulder and right elbow discomfort. In 2017, he made 22 starts and dealt with lower back discomfort. He made three starts in the playoffs in '17, including Game 7 of the World Series. He threw four scoreless innings in relief to close out Game 7 of the AL Championship Series against the Yankees.

Even without McCullers, Keuchel and Morton, the Astros have solid starting pitching options for next year after Verlander and Cole. Brad Peacock and Collin McHugh, who were moved to the bullpen from the rotation this season, will likely be back in the rotation mix in the spring, along with up-and-comers Josh James, Framber Valdez and lefty Cionel Perez.
Still, expect the Astros to explore adding a veteran starting pitcher to slot behind Verlander and Cole, both of whom had terrific seasons in 2018. The fact McCullers (128 1/3 innings), Keuchel (204 2/3 innings) and Morton (167 innings) combined to throw 500 regular-season innings last season, leaves the Astros with some work to do this offseason in terms of starting pitching.