Per Chandler Rome of the Houston Chronicle, the reigning American League MVP flew back to Houston on Sunday to have his knee re-evaluated.
Astros manager A.J. Hinch added that Altuve wouldn't be activated for the team's two-game series against the San Francisco Giants starting Monday.
"I think it feels like (a setback) only because we've eliminated San Francisco as a possibility," Hinch said. "I don't know that we can consider it a setback other than we can consider that he needs more time to heal."
Injuries had never been much of a problem for the second baseman in his career, averaging 154.2 games played in his six full seasons in the majors. He only missed 22 total games in the past four seasons, earning four All-Star selections and an MVP award in this span.
Unfortunately, he hasn't been as lucky in 2018, as a knee injury forced him to go on the disabled list for the first time in his career.
The latest injury also adds to what has been somewhat of a disappointing year for the 28-year-old.
While he is still playing at an All-Star level with a .329 average, his nine home runs and 14 stolen bases are a bit of a step back from what we have seen in the past. For instance, he hit 24 homers in each of the previous two seasons and stole 32 bases in 2017.
Houston has enough depth and offensive firepower to survive a short stretch without Altuve, but it would be difficult for the team to defend its World Series title without its most consistent player.
Utility player Marwin Gonzalez should be able to handle second base duties until the superstar is back on the field.