With the Fire in need of a goal, defender Jalil Anibaba picked up the ball on the right touch line, rocked back and tossed a 30-yard bomb in to the box.
"[When I was growing up] you had to throw the ball in with two hands, not one," Kreis said. "We're seeing a lot of players throwing almost completely with one hand."
Kreis was also upset with his team's defensive lap. Midfielder Yordany Alvarez appeared to drift off Amarikwa after the ball was thrown in, leaving teammate Nat Borchers to try to defend to men.
"It seems like every other team in the league has [a player capable of making a long throw in] except for us," Borchers said. "It's frustrating for us because every time the ball goes out for a throw in our half of the field, it's a set piece. But again, we have to deal with those things better if we want to be an elite team in this league."
Kreis, meanwhile, said he might be willing to make a statement.
"I'm tempted maybe the next game to send out my players and throw the ball in with one hand and see if that gets called against us," Kreis said. "Because I just think it's ugly. I think if you're going to throw the ball in long, you need to do it legally with both hands."