Lance McCullers Jr. will not be ready to go for the Houston Astros on Opening Day. The veteran starting pitcher said on Wednesday he underwent an MRI and it revealed a small muscle strain that will sideline him for several weeks.

After undergoing Tommy John Surgery in 2018, which forced him to miss the entire 2019 season, and then missing most of Houston’s 2021 postseason run and a majority of the 2022 season with a strained flexor muscle, McCullers’ latest issue is considered to be minor, and should not hamper him from being in the rotation long-term, he said on Wednesday.

Regardless of the severity of the injury, McCullers’ muscle strain will cause the Astros to have to shake things up with their starting rotation, at least to begin the season. Here is what it could look like.

Even before McCullers’ injury, Framber Valdez was likely going to be the Opening Day starter for the Astros. The questions begin behind him.

McCullers could have been Houston’s day two starter. The Astros still have plenty of options to choose from, but the edge could go to Cristian Javier, who recently signed his five-year extension earlier this month.

Luis Garcia and Jose Urquidy, two players that have started games in the past for Houston, likely have locked down their positions as well. With McCullers’ injury, it likely also secures a spot for Hunter Brown in the starting rotation.

Prior to McCullers’ injuries, there were questions about whether Brown would be in the rotation, if Houston potentially went with a six-man starting rotation, or if the Astros moved Brown or another pitcher to the bullpen. That is no longer a question.

In what could be a silver lining, the injury likely means it will be a trial by fire for Brown, who started two regular season games for the Astros in 2022.

It also opens up an opportunity for other pitchers, including Forrest Whitley, who has yet to pitch a single inning in the majors, J.P. France, Shawn Dubin, and Brandon Bielak. All four players have a chance to be on Houston’s major league roster while McCullers is out.

All four players also started games in 2022 for the Astros’ Triple A affiliate, the Sugar Land Space Cowboys.

That is something worth noting because on Houston’s current roster, only Ryne Stanek, Rafael Montero and Brandon Bielak are pitchers outside of Valdez, Javier, Urquidy, Garcia and Brown that have experience starting multiple games in a season at the MLB level.

For Stanek, they came in 2018 and 2019 for the Tampa Bay Rays, who were known for their bullpen games. Montero last started a game in 2017 for the New York Mets.

Losing a starting pitcher the caliber of McCullers to start the season is a significant loss, and in the pitcher’s own words, a frustrating one.

For now, the Astros have enough depth to absorb it for the start of the season. The biggest storyline to keep an eye on in the coming weeks is if it truly is just a minor injury for McCullers.