Patriots TE Rob Gronkowski does not travel with the team for its matchup with the Cardinals. Adam Schefter provides the latest on Gronkowski's condition and how New England will adjust on Sunday. (1:42)

FOXBOROUGH, Mass. -- The New England Patriots have officially downgraded tight end Rob Gronkowski, left tackle Nate Solder and right guard Jonathan Cooper to out for Sunday's season opener at the Arizona Cardinals, so now the question is, "Who fills the void?"

At tight end, Martellus Bennett will be counted on heavily. He had seven catches for 62 yards in the preseason, and while he had some up-and-down moments, he seemed to develop a nice rapport with quarterback Jimmy Garoppolo.

The Patriots also have seven-year veteran Clay Harbor (two catches, 23 yards in preseason) and second-year player AJ Derby, who was one of the surprises of training camp and the preseason with a team-high 15 catches for 189 yards and one touchdown.

The Patriots likely are going to rely heavily on Martellus Bennett on Sunday night, in the absence of tight end Rob Gronkowski. Fred Kfoury III/Icon Sportswire

Keeping four tight ends on the initial 53-man roster was one greater than the norm. The Patriots might have done it regardless of Gronkowski's hamstring injury, and that depth should help them, even though it's always going to be a drop-off when Gronkowski isn't on the field.

While Gronkowski's value is often measured in catches and touchdowns, former Patriots assistant to the coaching staff Michael Lombardi also pointed out Friday how the tight end also makes things easier for quarterbacks before the snap.

"When Gronk's flexed away from [the line of scrimmage] and a [linebacker] is with him ... every quarterback in the world knows it's man-to-man. If there would have been a corner out there on him, then they know it's zone," Lombardi said during his weekly appearance on Boston sports radio WEEI. "So Gronk's a great indicator. It really helps a quarterback, especially when you're playing against a team that does a lot of multiple things on defense."

Thus, Gronkowski's absence will make life harder before the snap for Garoppolo, who will make his first career regular-season start on Sunday night.

It also doesn't help Garoppolo that he will be without the team's best blindside protector in Solder. In fact, the loss of Solder, who injured his left hamstring in the preseason finale Sept. 1, is arguably just as much of a blow as losing Gronkowski, because the depth at offensive tackle is even thinner than at tight end.

The Patriots have a couple of options on how to proceed, and if the preseason is any indication, the leading candidate is third-year man Cameron Fleming. When Solder left the preseason finale, Fleming was the choice to replace him. While Fleming is more of a natural right tackle, he filled in on the left side in an emergency situation in 2015.

Fourth-year player LaAdrian Waddle is another option, and the team could also move third-round draft choice Joe Thuney to the left tackle spot, as he played there at NC State. But Thuney has been locked in as the top left guard since the first practice of the spring.

Meanwhile, Cooper's absence will open the door for either second-year player Shaq Mason (if he's recovered from a hand injury) or 2016 sixth-round pick Ted Karras at right guard.