Chicago Bears center Hroniss Grasu missed the entire 2016 season after suffering a torn ACL in his knee in August. He'll need to work very hard to earn a roster spot in 2017.

The former Oregon center entered the 2016 season as the presumed starter at center after starting eight games in 2015, but the knee injury disrupted his and the team's plans for the season. Now, Grasu could find himself on the outside looking in at the Bears roster.

Left guard Cody Whitehair came on in place of Grasu and played all 16 games at center during his rookie season in 2016. The Bears may be reluctant to move Whitehair out now that he has a year of experience, along with 2017 OTAs and minicamp to drawn on.

Another issue is while Whitehair possesses versatility to play different positions, the Bears see Grasu as a center, which could limit him.

"I view Hroniss more as a center-only," Bears general manager Ryan Pace told reporters in January. "If he comes back, that'd be the position he's competing for."

What might help Grasu is another former Oregon star, Kyle Long. Long is being shifted from right guard to left guard this season, but he's still recovering from a severe right ankle injury and torn labrum in his left shoulder. The ankle required surgery and then he experience complications from the anesthesia administered during surgery. The complications caused Long to lose nearly 60 pounds and he only recently closed in on his playing weight of 320. Long opted to rehab his shoulder instead of having surgery.

There is speculation that Long could be placed on the Physically Unable to Perform (PUP) list to start the regular season, meaning he would miss the first six games of the season. If Long is placed on the list, the Bears could move Whitehair to left guard to replace Long and insert Grasu at center.

The Bears could opt to simply insert backup Eric Kush into Long's spot and minimize any disruption on the offensive line. Kush started in four of the eight games he appeared in last season.

Should the Bears opt for Kush, that would make Grasu's chances for a roster more difficult. If the Bears decide to carry eight offensive lineman this year, which could place Grasu on the bubble.

-- Geoffrey C. Arnold | @geoffreyCarnold