GREEN BAY – On Sunday and Monday, Jordy Nelson’s receiving mates were coming to grips with the reality they’d be without their star and leader for the entire 2015 season.

On Tuesday, their thoughts shifted to the fact that the regular season begins in 19 days.

“It’s the urgency. We’re a couple weeks out from the season opener now, and we need to know who we can count on,” said Randall Cobb, suddenly the most veteran receiver in the group.

“Who are the guys that are going to step up and make those plays for us in those critical times during the season? We have to find that out. There’s not a lot of time.”

There are two preseason games remaining, and while it’s obvious second-year pro Davante Adams will now start alongside Cobb – who declared his new running mate “poised for a breakout year” – the rest of the pecking order is to be determined.

In practice on Tuesday, rookie third-round draft pick Ty Montgomery took the first snap in the three-receiver set with the No. 1 offense, but Jeff Janis and Myles White will likely get opportunities, too, as the preseason continues.

Cobb referred to all of them as having both “ability” and “potential,” but translating that into running the offense the way Aaron Rodgers wants and expects it to be run is another thing entirely.

Just as Cobb did four years ago, and just as Adams did last year, the young receivers must get on the same page with Rodgers and earn his trust, quickly.

“That’s the most important thing right now,” Cobb said. “It’s a daily thing. It’s something you have to do in practice. It’s something you have to answer his questions in the meeting room. You have to be accountable and not make the mistakes.”

Building that rapport should be accelerated now that Montgomery, Janis and White will be getting more than just token practice or game reps with Rodgers.

Still, given what little remains of training camp, the task is significant.

“As a receiver, you always want to be on the same page with your quarterback,” Montgomery said. “Who knows how much time until that happens?

“I know what to do. I know my plays. It’s not something I’ve spoken to Aaron about, so I can’t speak on his behalf, but I feel confident.”

Nelson, who spoke to reporters on Tuesday, expects to be around to help with the process, reviewing film and providing tips and pointers as he goes through surgery and rehab. His off-the-field leadership will still be present when possible.

“It means a lot,” Janis said. “He’s got so much experience and he knows so much about the offense. Just to have him by my side and help along, it’s going to be good.”

Nelson’s counsel alone, though, won’t make up for 98 receptions, 1,519 yards and 13 touchdowns.

Veteran offensive tackle Bryan Bulaga referred to compensating for Nelson’s absence as a “unit thing” for the entire offense. As Nelson, who will aim to return for the start of training camp in 2016, expressed his confidence that the offense could still roll along without him, he suggested the same thing.

“The young guys will just have to make that step. It’s going to be quicker than what they expected probably, but I think we have a lot of guys to lean on,” Nelson said. “Our tight end group is great. Eddie (Lacy) and James (Starks) in the backfield.

“Being as balanced as we are is big for us, and hopefully we can continue that. I don’t have any question they’ll be able to move forward and be as good.”

They just have to get to that point in a hurry.

“We don’t really have time to sit around and mourn too much,” Adams said. “It’s unfortunate this happened, obviously, but I feel like I’m ready for a bigger role.”

Added Cobb: “We’re going to dedicate this season to him and doing everything we can to make sure this train continues going in the direction we were leading toward before he went down.”

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