Johnson said: "At the time it was right for Michael McIndoe to move on and the search was on to find another left-sided player who could affect the game. Michael did that at the start but not near the end of his time here.
"There aren't many players like that around, and we are aware of that situation. We also don't have cover for Jamie McAllister.
"We are extensively looking for the right left-sided player to give us balance.
"If we do find the right one we'll bring them in. It's not that I don't want to play wingers. The best wingers are the ones [other teams] don't want to let go anyway. I promise we're looking."