Theismann: RG3's upcoming preseason game 'biggest' of his life

Aug 13, 2015; Cleveland, OH, USA; Washington Redskins quarterback Robert Griffin III (10) on the sidelines during the first quarter of preseason NFL football game against the Cleveland Browns at FirstEnergy Stadium. Mandatory Credit: Andrew Weber-USA TODAY Sports

Robert Griffin III has played in big-time college football games at Baylor and an NFL playoff game in his rookie season.

But former Washington Redskins quarterback Joe Theismann believes this Saturday's preseason game against the Baltimore Ravens is "probably the biggest game" of his life.

"It's a preseason game, but this is probably the biggest game that Robert Griffin has ever played in his life," Theismann said Monday on NewsChannel 8 via the Washington Post.

"I think it's important that Robert get the work in," Theismann said. "He has 10 days to get ready. He'll probably have two or three practices, at least, to get ready for what will be a full dress rehearsal against some pretty good pass-rushers. [Suggs] and [Elvis] Dumervil bring it as well as anybody in football. So, it's going to be a great test for this offensive line, it's going to be a great test for Robert going out. I fully expect him to play, hopefully a full half and then some. And then we can sit down and really make an evaluation, OK, where is he?"

Griffin suffered a concussion and a stinger during last week's preseason game against the Detroit Lions. He finished that game 2 of 5 for 8 yards on four possessions.

Griffin has been slowed by injury and a lack of production since his stellar rookie season in 2012. He was limited to nine games last season after suffering an ankle injury and finished with just four touchdowns and six interceptions.