Valdez, 27, is coming off the best start of any pitcher this postseason after going eight innings and giving up just one run against the Boston Red Sox in Game 5 of the American League Championship Series. He'll be opposed by Braves right-hander Charlie Morton.
"I expect a very formidable foe," Astros manager Dusty Baker said on Sunday. "When you get down to the last two teams, you can't overlook anybody.
"David [the Braves] just slew Goliath. They have a good team."
Astros righty Lance McCullers has been all but declared out for the World Series after missing the ALCS with forearm tightness. A decision on centerfielder Jake Meyers (shoulder) is pending. Rosters don't have to be turned into the league until Tuesday morning. The series features several connections between the Astros and Braves, including one that involves Baker, Braves manager Brian Snitker and the late, great Hank Aaron.
"Hank Aaron hired [Snitker] and Hank Aaron was very close to me," Baker said. "To be in the year of Hank Aaron's celebration, to be in the year of Hank Aaron's passing ... it's very special to go back to Atlanta. It's going to be a storybook ending for all of us."
There's a family connection between the teams as well, as Astros coach Troy Snitker is the son of the Braves manager. The two have been discussing the possibility of meeting in the World Series since both of their teams missed out on making the Fall Classic by a game last year. "It's unbelievable," the younger Snitker said. "It's something we were praying and hoping it would happen. For our family, I don't know if we can envision anything bigger than this."
Troy was asked who his mom is going to be rooting for.
"I have no idea," he said with a smile. "I don't know if she's going to clap when something happens or cry. My guess is that she's going to be a mess.
"It's cool to think about two pennants in the same house. One of us is bringing home the trophy."