Astros' McCullers to miss 2019 after Tommy John surgery

Houston Astros right-handed starter Lance McCullers Jr. will miss the 2019 season after undergoing Tommy John surgery on Tuesday, the team announced.

General manager Jeff Luhnow acknowledged Monday that McCullers was dealing with an elbow problem and that he'd "been seen by some doctors," though surgery wasn't a given until Tuesday, according to Chandler Rome of the Houston Chronicle.

The 25-year-old has been a key piece of the Astros rotation for four seasons. He went 10-6 with a 3.86 ERA and 142 strikeouts in a career-high 128 1/3 innings in 2018.

This is the most significant injury of McCullers' playing career - though he's spent some time on the disabled list. He opened the 2016 campaign on the shelf with shoulder soreness, was sidelined with a recurring back injury in 2017, and his elbow forced him out of action for than a month this past season.

Due to arbitration, McCullers is not poised to hit free agency himself until 2022. He'll look to rejoin the Astros for the 2020 campaign.

The Astros suddenly find themselves thin at starting pitcher - a position that was a point of depth for the club this season. In addition to McCullers being out for 2019, both Dallas Keuchel and Charlie Morton are free agents.

Luhnow and the Astros aren't overly concerned just yet, though.

"We don't feel like we're in a position of panic or have to overact," he said, according to Brian McTaggart of MLB.com. "That being said, we are going to explore the trade market, we're going to explore the free-agent market for starters to try and put together as solid of a rotation as we can."

Right-hander Collin McHugh, who has started 102 games for the Astros since 2014, has thrown his hat in the ring to help fill the gap.