BALTIMORE — In search of an offensive spark, the Minnesota Twins are promoting Trevor Larnach and sending Matt Wallner back to Triple-A St. Paul. Wallner struggled to make contact, let alone produce early in the season. He’s struck out in more than 50 percent of his plate appearances to start the season and routinely looked overwhelmed. The outfielder had only two hits in 25 at-bats this season, one of which was a homer off a position player Saturday against the Detroit Tigers. The Twins likely hope a reset will be helpful for Wallner, who played a critical role in helping…