The Detroit Lions are reportedly interested in Cincinnati Bengals defensive coordinator Mike Zimmer, and it turns out they may have interest in Cincinnati's offensive coordinator as well. According to Adam Schefter, Bengals offensive coordinator Jay Gruden is on the Lions' "coaching wish list," as is San Diego Chargers offensive coordinator Ken Whisenhunt.
Interestingly, the Bengals and Chargers are meeting each other in the playoffs on Sunday afternoon. This is why the Lions haven't been able to talk to Zimmer, Gruden or Whisenhunt yet; those coaches have been busy getting ready for a playoff game. Next week, however, all of those coaches will be available to speak with the Lions and other teams because NFL rules allow for interviews to take place.
Gruden, who is Jon Gruden's brother, has been the Bengals' offensive coordinator since 2011. He has played a major role in the development of quarterback Andy Dalton, and he actually won four ArenaBowl championships as a quarterback. (He also won two more as a head coach.) Clearly, he fits the profile of someone who would be able to come in and help Matthew Stafford get better.
It's unclear at this time if the Lions are actually planning to interview Gruden, but if he is in fact on their coaching wish list, I'd imagine a conversation will take place at some point next week.