Time to step up: JC Tretter

GREEN BAY, Wis. -- Coach Mike McCarthy and general manager Ted Thompson say it every offseason: It is not the rookies who will make the difference for the Green Bay Packers but rather the returning players.

With that in mind, we continue our look at some returning players who need to take their game to another level in 2014.

We wrap up this series with center JC Tretter.

Why he needs to step up: When the Packers decided not to get into a bidding war with the Tampa Bay Buccaneers for the services of center Evan Dietrich-Smith, who signed a four-year, $14.25 million contract, it ensured the Packers would have their fourth starting center in as many seasons. This time around, the Packers are looking for some stability in the position after going from Scott Wells (2011) to Jeff Saturday (2012) to Dietrich-Smith (2013).

What he has to do: Not only has Tretter never played center, he has never even played in an NFL game – not even a preseason game. Last year as a rookie, the fourth-round draft pick from Cornell broke his ankle during OTAs and missed the rest of the offseason, all of training camp and began the season on the physically unable to perform list. Although he returned to practice on Nov. 19 and was added to the 53-man roster on Dec. 10, he was not active for any games. He showed enough in offseason practices this year to convince the Packers that he can be their next starting center, but until he does it in live action, they won't know for sure.

Outlook: Tretter took every snap with the starting offensive line during the offseason and enters training camp as the favorite to win the job. The only other true centers the Packers have on the roster are former practice-squad player Garth Gerhart and rookie fifth-round pick Corey Linsley of Ohio State. The Packers would rather not move guard T.J. Lang, who filled in at center during two games last season when Dietrich-Smith was injured. Utility linemen Don Barclay also could play center if necessary.

Quotable: "I think it's JC's [job] to lose right now," quarterback Aaron Rodgers said.

Previous installments

Part one: Morgan Burnett

Part two: Nick Perry

Part three: Datone Jones

Part four: Jerel Worthy

Part five: Brad Jones

Part six: Davon House

Part seven: B.J. Raji

Part eight: Andrew Quarless

Part nine: Derek Sherrod