Entering Wednesday's contest against the Blue Jays, Wieters was hitting .196/.292/.337, with two homers and seven RBIs in May after batting .279/.364/.574 in April with six home runs and 15 RBIs.
The funk has only gotten worse recently. Over his last 11 games, he is 3-for-36, but manager Buck Showalter is not concerned.
"Some of it's the wear and tear of catching," Showalter said. "Like all hitters, you are going to have ups and downs in the year. You try to minimize them as much as you can. Matt will start swinging the bat well again, and I thought he has had some good at-bats the last couple of games.
"With a guy like Matt, you figure if he's struggling statistically, someone is going to pay for that down the road. He is going to make somebody pay. I trust him."
Wieters was ejected for the first time in his career in the fifth inning of Tuesday's loss to the Blue Jays for arguing balls and strikes.