JACKSONVILLE – The question remains very much a question.

That means the status of the Jaguars' cornerbacks for Sunday likely won't sort itself out until shortly before kickoff.

Starting cornerback Alan Ball on Friday was ruled out for Sunday's home game against Miami, with Dwayne Gratz – the player who could move into the starting lineup to help make up for Ball's absence – entering the weekend questionable.

Those are some serious unknowns, and they likely won't be known until Sunday morning.

"We've had to adjust a little bit," Head Coach Gus Bradley said as the Jaguars (1-6) prepared to play the Miami Dolphins (3-3) at EverBank Field Sunday at 1 p.m.

"Sometimes certain position groups may get hit throughout the season, and this week it's the corner spot."

Ball, who on Wednesday sought a second opinion on a biceps injury sustained against Cleveland Sunday, officially was ruled out Friday. While Ball was considered very doubtful throughout the week, Gratz's situation was more of a surprise.

He practiced Wednesday, and then experienced tightness in his hip Thursday. He was listed as limited on the Thursday injury report, then did not practice Friday.

"We'll see how it goes tomorrow, then on game day we'll work it out and go from there," Gratz said. "There was no specific thing. It was just tight and we tried to loosen it up and go out there and play. It didn't work out as well as I planned it, but we're being smart and doing the right things."

Gratz is officially listed as questionable for Sunday.

The scenarios at corner are then as follows:

*If Gratz plays, he will start at left corner with Demetrius McCray moving to Ball's right corner spot. Gratz started the first four games of the season at left corner before sustaining a concussion. McCray has started there since, getting roughly twice the reps as Gratz the past three weeks.

*If Gratz doesn't play, second-year Jeremy Harris will start at right corner with McCray staying at left. It would be Harris' first NFL start.

*Veteran Will Blackmon will remain the nickel corner, but would move to corner if Harris or McCray are injured. In that scenario, safety Sherrod Martin likely will move to the nickel to replace Blackmon.

Harris, who spent last season on injured reserve after being selected in the seventh round of the 2013 NFL Draft from New Mexico State, has played in one NFL game. That was against Pittsburgh at EverBank Field on October 5.

"What I like about Jeremy is when he is in a competitive situation like one on ones he really competes," Bradley said. "You really see him compete play in and play out and that was my challenge today. That mentality is what you need every play on the field, and if he does that he'll compete."

Blackmon agreed.

"I'm not worried about him at all," Blackmon said. "He stays on top of it and plays the ball. I have no issues worrying about him. We'll be fine. We compete every day all week. The offense goes at us and we go at them, so I'm not worried."

Also around the Jaguars Friday:

*Defensive end Andre Branch was officially ruled out with a groin injury that he sustained last week against Cleveland. He is expected to miss about six weeks. Ryan Davis is expected to play Branch's role as a backup Leo defensive end. …

*Center Luke Bowanko (ankle), running back Toby Gerhart (foot) and safety Craig Loston (hamstring) all worked full Friday and are listed as probable for Sunday. Gerhart has missed the last two games after starting Weeks 1-5 and playing through the foot injury since the regular-season opener. While Denard Robinson is expected to remain the feature back, Bradley on Friday said Gerhart likely will get more repetitions than reserve Storm Johnson.

*Rookie cornerback Aaron Colvin did not practice for a second consecutive day after working limited Wednesday. He remains on the Physically Unable to Perform list, with the Jaguars having a three-week window from Wednesday – his first practice with the Jaguars – to determine whether to activate him or place him on injured reserve. "We have three weeks to decide," Bradley said. "I think you'll see it get amped up more for him." …