Martin Mayhew’s words have echoed for months. The Detroit Lions general manager said if a cornerback doesn’t make it in three years in the NFL, he’ll never make it. Mayhew, a former NFL cornerback, knows something about the position.

Here are three cornerbacks, who were all drafted in 2012, whose futures could be on the line in training camp:

1. Bill Bentley made a big step in 2013. He seemed to fit in comfortably at the nickel position. He needs to expand his repertoire and show he can also play at corner if needed. With Chris Houston gone, the cornerback ranks have thinned. It should be a good opportunity for him and ...

2. Jonte Green has played in 24 games the last two season with seven starts.  He’s made some big plays, but has been inconsistent. Green looked better in minicamp than he did in OTAs, so that’s something.

3. Chris Greenwood needs to stay healthy and on the field. He missed his rookie training camp and season after sports hernia surgery following OTAs. He finally got off the practice squad and onto the field for the final three games of 2013. He missed a few days in the offseason with injuries, but was working in minicamp. They drafted him for his athletic ability. Now he needs to take the next step.

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