With start QB Robert Griffin III sitting out pre-season as he recovers from a knee injury, the last thing the redskins need is Cousins also going down, as he would be the starter if Griffin cannot make the regular season opener.
Cousins hobbled out of the second quarter with a foot injury after getting caught from behind scrambling for the sideline - with initial reports suggesting a mid-foot sprain is the cause of the problem.
Rex Grossman replaced Cousins and threw a touchdown pass, but Washington will be hoping Cousins is fit enough to start the season even if he misses the rest of pre-season, as he is the back-up plan for Griffin.
"When I first did it, it didn't feel like it was anything serious," Cousins said. "It feels almost like a sprained ankle, just in the middle of my foot."
Surgeon James Andrews checked Griffin over after he warmed-up before the game, and even though coach Mike Shanahan joked with his QB about sending him into the game - patience is still the key as the team look to field Griffin in their first game of the season.
"He watched him out on the field. Then he brought him in and obviously checked him out," Shanahan said. "It's the first time that he's checked Robert since we went to training camp, when (Andrews) approved that he could practice. He felt very good about his progress.
"But, again, he's going to come back in a couple weeks after our pre-season's over, re-evaluate him again, and then he'll give us the 'Yea' or 'Nay.' "
Roy Helu ran in a 30-yard TD for the Redskins, who won an error-strewn game on the back of solid defence hustling the Steelers throughout - although they lost defensive tackle Barry Cofield to a hand injury.
Pittsburgh lost their second game in a row in pre-season with another scruffy performance, and the troubles continued for rookie running back Bell.
Bell missed the first game with a sore knee, but on his Steelers debut he lasted just one series before he left with what also looked to be a foot injury.
Jonathan Dwyer continued as running back replacing Bell, but the Pittsburgh backfield lost more bodies in the game as running back Baron Batch and full-back Will Johnson both failed to complete the game.