The battle for the Steelers No. 3 wide receiver spot behind starters Hines Ward and Santonio Holmes had not been resolved -- and probably won't be.
Arians said both Limas Sweed and rookie Mike Wallace will serve as the No. 3 wideout at times.
"There are different packages for both those guys so there's not really a third guy; it depends on the package that they're in right now," Arians said. "It gives us some flexibility that way."
The Steelers will likely open the season dressing just four wide receivers with teams only allowed to activate 45 players for games.
Arians said he "would doubt it right now" that veteran Shaun Mcdonald will dress for games.