Jason Campbell is not a bitter guy. He says it wouldn’t do any good anyway. But there was an unmistakable edge in his voice last August in Bourbonnais when the Chicago Bears quarterback was talking about the broken collarbone that ended his season last year and, as it turned out, his career with the Oakland Raiders.

“It was a bone, not anything affecting my throwing motion,” Campbell explained.

He had led the Raiders to a 4-2 start, but in a panic move after the injury, the Raiders traded a first-round pick (in 2012) and second-round pick (in ’13) to the Cincinnati Bengals for quarterback Carson Palmer. Oakland ended up finishing the season 8-8 and out of the playoffs.

“It’s crazy sometimes that this is your eighth year and you still feel like you have to prove yourself,” Campbell said this summer.

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