Wheeler hasn't appeared in two consecutive games, and Hackworth said he is now back at forward, where he played in 2013.
"It's 100 percent [the coaches'] responsibility," Hackworth said. "I think any time you're looking for solutions, you're going to try things."
The 3-0 shutout Saturday night against Chivas USA comes with a caveat: Chivas USA has scored just 11 goals this season, second fewest in the league.
The game Saturday against the Vancouver Whitecaps (5-5-2) at PPL Park will be the Union's final game before the league's World Cup break.
The break will give the coaching staff time to right its wrongs and scour the market for players who can help when league play resumes June 28.
"Our main responsibilities are going to be trying to scout players, look in every possible situation to see if there's a player that we can bring in that we can add, while preparing for this next phase of our season," Hackworth said.
Before the Union (3-5-7) get to that point, they will have to deal with a strong offensive team in the Whitecaps.
"We feel like if we string together two victories and two performances that we'll put ourselves back on a place where we all want to be," Hackworth said.
Though the team was just two points out of a playoff spot in the Eastern Conference, only the Houston Dynamo can match the Union's 15 games played. The conference's fifth-place team, Toronto FC, has five games in hand on the Union.