Wieters, 28, had Tommy John surgery on his right elbow last June and caught his first spring training game on Tuesday.
Showalter said the team doesn’t know if Wieters will be ready to start at catcher in the team’s home opener next month.
"It’s still a distinct possibility, but if [he's not ready] then, shortly thereafter," Showalter said Wednesday. "I don’t think we are at a point yet [to know]. We’ll see how the tendinitis manages."
Wieters was limited to 26 games last season, but he was still named to his third All-Star team. During his last full season in 2013, he batted .235 with 22 home runs and 79 RBIs.
Without Wieters last season, Caleb Joseph became the team’s starting catcher. In 82 games, he had nine home runs and 28 RBIs while batting .207.
Baltimore reached the ALCS last season before being swept by Kansas City. The Orioles open the season on April 6 at the Tampa Bay Rays.
- Paul Palladino