Mark Wahlberg Offers His Thumb To Injured Jose Altuve, 'I'm A Big Fan'

Mark Wahlberg is diving head-first into his Houston Astros fandom ... going as far as to say he'd donate one of his thumbs to help superstar Jose Altuve get back from his injury!!

The 51-year-old actor is usually a Boston Red Sox fan, but has been supporting the 'Stros due to their ability to wreck the New York Yankees lately. Mark has been welcomed to the H-Town fanbase with open arms ... and even gave the ceremonial "Play Ball!!!" call at Thursday's Opening Day game against the Chicago White Sox.

Before his big moment, Mark raved about Altuve's teammate, Alex Bregman ... calling him a good friend and his "favorite Yankee killer of all time."

"I am an Astros fan," he added. "Listen, I live in Nevada now, I'm a fan of real talent. And, you know what, they have an amazing team, and he has amazing talent, but he's also an amazing person, so I'm a big fan of his, especially."

As for Altuve -- who is out indefinitely after breaking his thumb playing for Venezuela during the World Baseball Classic -- Wahlberg says he's willing to help out.

"I am also willing to donate either one of my thumbs to Jose Altuve, for sure," Wahlberg told reporters. “So we’re all good. I’m a big fan."

Mark wasn't the only celeb in town for the big game -- Megan Thee Stallion also came through to throw the first pitch!!

As for the game, the Astros lost to the White Sox, 3-2.