John Niyo suggests it in an article in the Detroit News this morning regarding FAs:
Keenum, who played last season in Washington on a $3.5 million salary, might also make sense. He has 62 starts under his belt, has completed 62.4 percent of his passes during his career with 75 touchdowns to 47 interceptions. That would be the most reliable performer the Lions would have had behind Stafford since Shaun Hill.
Personally, I like the idea.