Sammy Watkins, LeSean McCoy among injured Bills who may not play Titans

While the Bills are hopeful Sammy Watkins will be available Sunday, they are not sure how severe his injury is. Tom Szczerbowski/Getty Images

The Buffalo Bills managed to stay mostly healthy through the first two weeks of the season, but their luck in that area has eroded over the past two games.

From Sammy Watkins to LeSean McCoy and others, the Bills could be without several players as they travel this weekend to meet the Tennessee Titans.

Here is an update for each of the Bills' injured players:

Watkins: After injuring his calf in Week 3, Watkins sat out Sunday's game and remains questionable this week. "Everything points to that it’s not that severe," general manager Doug Whaley said Tuesday on WGR 550. "We’re hoping to see how he responds this week. We have our fingers crossed that he may be in this week. There’s no indication that it’s going to be something long term. But I never say never with injuries, especially with soft tissue injuries. He could go out there and test it and something could go wrong. Soft tissue injuries are harder to predict."

McCoy: The star running back told reporters that he suffered a setback in his recovery from his hamstring injury the Thursday before the Bills' Week 3 game. He promised himself that he won't play until he's 100 percent healthy. Fox Sports reported Sunday that McCoy could miss 3-4 weeks as he works back to full health, although Rex Ryan insisted that his medical staff hasn't informed him of such a timetable and that McCoy remains "day-to-day, week-to-week."

Karlos Williams: McCoy's replacement, Williams told the Bills' medical staff that he wasn't feeling well several hours after Sunday's game and was diagnosed with a concussion by Monday evening. He's considered day-to-day, Whaley said, but the Bills signed running back Boom Herron as insurance. It's not out of the question that Williams returns this weekend. That's exactly what safety Corey Graham did after suffering a concussion in Week 1 before playing again in Week 2.

Aaron Williams: After sitting out a week because of a neck injury, Williams returned to practice last week on a limited basis but was ruled out for the game by Friday. If he ramps up his practice participation this week, he could be ready to play by Sunday.

Bacarri Rambo: Williams' replacement the past two weeks, Rambo suffered a deep quad bruise, Whaley said Tuesday. Fox Sports reported later Tuesday that Rambo is expected to miss at least a week, which would elevate Duke Williams on the Bills' safety depth chart.

John Miller: The Bills' rookie guard left their Week 3 game with a groin injury and did not practice or play last week. He has been seen in the locker room but it's not known whether he'll practice this week. His replacement, veteran Kraig Urbik, received the worst grade (minus-3.4) of any Bills' offensive lineman Sunday from Pro Football Focus.

Marquise Goodwin: The Bills' oft-injured speedster has eased back into practice early this season after suffering broken ribs in the preseason. If he participates fully in practice this week, it will be a positive sign for his availability Sunday.

MarQueis Gray: After fracturing his forearm in Sunday's loss to the Giants, the Bills placed Gray on injured reserve Tuesday, ending his season. That will give more opportunities to Chris Gragg, who had been the fourth tight end on the depth chart.