It’s unclear at this point how serious a candidate Ravens offensive coordinator Jim Caldwell is for the head coaching openings with the Detroit Lions and the Washington Redskins, or if he’ll ultimately emerge as a candidate at Penn State as well.

But you can bet that like most coaches, Harbaugh already has an extensive list put together about potential assistants that he’d like to hire given an opening.

I’m not privy to that list, but I’d be surprised if the Ravens didn’t at least check in on Cleveland Browns offensive coordinator Norv Turner’s availability. Turner is still under contract with the Browns, but he reportedly questioned Cleveland owner Jimmy Haslam and CEO Joe Banner after this week’s firing of head coach Rob Chudzinski.

It still would be hard to imagine the Browns letting Turner go, though it can’t be ruled out because their new head coach may want to bring in his own offensive coordinator.

If that happens and Ravens had an opening at offensive coordinator, Turner would be a great fit. The Ravens have long had a tremendous amount of respect for Turner, his offensive mind and his skills as a play caller.

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While Harbaugh said Monday that there were no imminent plans for coaching changes, I’d still be surprised if run game coordinator Juan Castillo is back next year. It sounds like both sides could be ready for a parting at this point and Castillo, who has a really good reputation around the league regardless of what happened this year, shouldn’t have a huge problem finding another job.

That would be ideal for the Ravens and prevent Harbaugh from having to fire a good friend, though he’s done it before with Cam Cameron.

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One more coaching observation: it will be interesting to see if senior defensive assistant Steve Spagnuolo gets some feelers with the number of defensive coordinator jobs that might open.

The New York Giants would be one potential match if they decide to dump Perry Fewell or Fewell surprisingly gets the Redskins head coaching job. Spagnuolo was the defensive coordinator when the Giants won the Super Bowl in 2007, and he’s extremely well liked and respected by that organization.