Bears X-factors: When will Long, Trevathan, McPhee be ready?

Following two days of inordinate focus on the bottom half of the Bears roster — “Will Tanner Gentry make it through waivers?” — the attention turns to a much bigger issue Monday at Halas Hall: Which key starters will play against the Falcons in the season opener Sunday at Soldier Field?

After finishing 2016 with 19 players on injured reserve, the Bears again have injury issues heading into Week 1. Eight players who could be starters did not practice or were limited last week: guard Kyle Long, outside linebacker Pernell McPhee, inside linebacker Danny Trevathan, wide receiver Markus Wheaton, cornerback Prince Amukamara, nose tackle Eddie Goldman, defensive end Jonathan Bullard and nickel back Bryce Callahan.

But it’s the top of that list that bears the most watching. It’s one thing for your X-factor to be a player like Kevin White, who is unproven but has the potential to be great; or a rookie like Eddie Jackson, who could be inactive by midseason but has the potential to be a Pro Bowl-level starter. It’s another when the X-factors are proven veterans the team is counting on to not only play at a high level but also to lead others to play at a high level. And the Bears have three of those: Long, McPhee and Trevathan. Here’s a look at where they stand heading into the season:

Pernell McPhee

After spending the entire training camp and preseason on the physically unable-to-perform (PUP) list, McPhee was — a bit surprisingly — added to the active roster. On Monday, coach John Fox did not discount the possibility McPhee could play Sunday, even if it’s limited.

“In the words of our orthopedic [specialist], our trainer, our strength-and-conditioning coach Jason George, [McPhee is] ‘probably in the best shape he’s ever been in’ ” Fox said. “So we felt very confident just watching him move around [in practice].”

With two legitimate, quality starting pass-rushing linebackers in Leonard Floyd and Willie Young, the Bears not only can withstand McPhee’s absence, but also can give him limited snaps when he does get on the field. And that seems like the best plan of attack, because McPhee might not be able to handle the workload the Bears envisioned him playing when they signed him to a five-year, $38.75 million contract ($15 million guaranteed) in 2015. He has 10 sacks, one interception and two forced fumbles in 23 games with the Bears.

Kyle Long

The three-time Pro Bowl guard/tackle has been undergoing a long, arduous recovery from what Fox termed “a severely broken ankle” in Week 10 last season — a recovery that has seemed to almost decelerate during the preseason.

The Bears are more hopeful than expectant that Long will start against the Falcons. Since backup Eric Kush was put on injured reserve Aug. 8 with a hamstring injury, the Bears more often than not went to Plan C — starting Hroniss Grasu at center and moving center Cody Whitehair to left guard instead of just plugging Grasu or Tom Compton in Long’s spot as a place-holder.

“We’re hopeful for everybody,” was all Fox would say when asked about Long’s availability for the opener. “I can’t guarantee it. We’ll make that decision [90 minutes] before kickoff.”

Long is capable of great things. He made the Pro Bowl in his first two seasons in the NFL at guard, despite starting just four games at guard at Oregon. He held his own (and made the Pro Bowl) at right tackle in 2015 despite moving to the position at the start of Week 1 of the regular season. He played through a shoulder injury last season before the ankle put him on IR.

But this injury has flummoxed even Long at times, which leaves three huge questions entering Week 1: When will he start? How good will he be? And how long will he last?

Danny Trevathan

The veteran linebacker, who came to the Bears with Super Bowl credentials after starting on the Broncos’ championship team in 2015, has made surprising progress in his recovery from a torn patellar tendon he suffered in Week 12 last season. Figured to start training camp on the PUP list, Trevathan worked his way back into team drills by the end of the preseason, though he did not play in a preseason game.

Trevathan figures to practice with the first team this week before the Bears make a decision on whether he’ll actually start against the Falcons. For what it’s worth, Trevathan has a history of quick healing. In 2015, he underwent kneecap replacement surgery in January and started the final preseason game, 15 regular-season games and three playoff games en route to the Super Bowl championship.

But a patellar tendon is a particularly difficult recovery. The Bears need to make sure Trevathan isn’t at a greater risk of re-injury or a new injury by putting him on the field too soon. In 2014, Trevathan had two previous knee issues before the kneecap went. He played in three games that year.

So whether it’s luck, intuition or medical expertise, the Bears have some tough calls this week. And it doesn’t end there. They not only have to get healthy. They have to stay healthy.

Follow me on Twitter @MarkPotash.

Email: mpotash@suntimes.com