I have a cousin who is a lifelong and diehard Lions fan and I posed the question to him about this matter. He loves Stafford and is strongly rooting for him to do well with the Rams. His response regarding Stafford's occasional inaccuracies was:

"The finger is def the reason. He played with a broken back the final 3 weeks of a meaningless season 3 years ago. It came out when the season was over that he was getting surgery. He would never admit an injury is affecting his play."

Stafford has been part of this team for a very short period and I think we all recognize that that is his MO: to never discuss -- let alone blame -- injuries. It's an admirable quality and it certainly makes a lot of sense that the injuries to his hand (thumb and now the index finger) are affecting some of his throws. Frankly, how could it not?