Back in January, Spotrac’s Michael Ginnitti took at stab at what the Panthers would have to fork over in a Cam Newton contract extension. Ginnitti’s guess: 5 years, $108 million with $51 million guaranteed.He stuck with those numbers a day before the Carolina quarterback signed his 5-year deal worth $103.8 million with $54 million guaranteed. While the prediction wasn’t exact, it was pretty close, so it’s worth checking out Spotrac’s latest forecast for linebacker Luke Kuechly.Their prediction: A five-year extension worth $58 million. Add on the $11 million he’s guaranteed to make in 2016, and Kuechly’s average annual salary through 2021 would be $11.5 million. That seems fair.Kuechly isn’t going to be the league’s top-paid linebacker. The $101 million contract Kansas City gave Justin Houston last week is apples compared to Kuechly’s oranges since Houston’s is a pass rusher’s deal. But $11.5 million would set a record for the highest average given to an inside linebacker. Former Panther Jon Beason and retired 49er Patrick Willis still hold that mark at $10 million.Of current players, Pittsburgh’s Lawrence Timmons leads inside linebackers at $9.6 million a year.As BBR reported in early June, the Panthers want to get Kuechly locked in as soon as this summer. While many assume his deal will follow the same time frame as Newton’s, general manager Dave Gettleman can fast track this one now that he knows what he’s committed to his highest-paid player.With training camp fast approaching, it’s unclear if Kuechly and the Panthers will keep lines of communication open or just shelve everything until 2016. But considering how Kuechly’s focus is pretty much always just football, this could be a case where the two sides — or more specifically, Kuechly’s agent Tom Condon and Gettleman — can keep talking and eventually get something done before the season.