GREEN BAY - When the Green Bay Packers lost wide receiver Jordy Nelson to a season-ending knee injury in their second 2015 preseason game, they lost more than just a Pro Bowl performer who was Aaron Rodgers’ favorite target.

They also lost any semblance of a deep passing attack.

Without the speedy Nelson to worry about, opposing defenses cheated up, putting eight men in the box and daring the Packers to go long. Green Bay rarely could make them pay.

“Defenses were aggressive with us last year, no doubt about it,” Packers coach Mike McCarthy said after the NFL draft. “It started early in the season and continued and we didn’t get them out of it.”

No Aaron Rodgers on top 101 list for 2015

The Packers slipped to 25th in the NFL in passing (218.9 yards per game) and 29th in passing plays of more than 40 yards (six) last season.

When it came to hitting the home-run ball, the 2015 Packers were best remembered for two desperation plays: a 61-yard Hail Mary pass to tight end Richard Rodgers with no time remaining to beat Detroit 27-23 on Dec. 3, and another Hail Mary against Arizona, this one a 41-yard fling to Jeff Janis that sent into overtime a Jan. 16 playoff game the Packers went on to lose 26-20.

Receiver James Jones, signed to step in for Nelson, hit some big plays early until opponents started erasing him from games with their best cover corners. Second-year man Davante Adams, expected to step up after Nelson went down, was sidelined early by an ankle sprain and failed to produce after his return.

Janis, who caught seven passes for 145 yards and two scores in that Arizona playoff game, got his chance only because Adams was injured the previous week and slot receiver Randall Cobb was knocked out of the game early. Janis boasts blazing speed (4.37 seconds in the 40-yard dash at the NFL scouting combine), but a lack of precision in route running has restricted the 2014 seventh-round draft pick’s participation largely to special teams.

Janis figures to get more opportunities in the 2016 season after his breakout game against the Cardinals. And he will get a run for his money in the fleet-feet competition from fifth-round draft pick Trevor Davis, a wide receiver from Cal who ran a 4.42 40 at this year’s scouting combine.

Sam Seale, the Packers’ West Coast area scout who recommended Davis, put it this way when speaking about Davis after the draft.

“I’m an old Raider and I’m going to try to talk like my old boss (Al Davis) used to: Speed kills,” Seale said. “Once you have speed, that’s all you need. … I think he brings an extra dimension to this team.

“Last year sitting at home watching TV where everybody was daring us to go deep, I hope they do that with this kid. I’m hoping they do. I figure if they do that, after the first four, five games you won’t see that anymore.”

Trevor Davis eyes route to Packers success

And of course, the biggest cause for optimism is the anticipated return of Nelson, who said before the start of offseason workouts that he is progressing well in his rehab. Although Nelson will be 31 when the season starts, he’s not worried about losing a step.

“I’m excited to play,” said Nelson, who posted a 4.5 time in the 40 before the Packers drafted him in 2008. “I think I said when it happened it will be the first time in 18 years I hadn’t played football in the fall. I’m excited to be back out there. I told my wife the other day I’m excited to be sore, it’s a good sore to have. You look forward to that.”

You can be sure McCarthy is looking forward to it, as well.

“I feel really good about the wide receiver group; I’m not concerned about overall speed at all,” he said. “You can just make that clear right now. It’s been great that we’ve been able to add 4.3 to the mix. But we’ve got guys who can run, that can run fast, that can go over the middle. I think getting the health of that unit back will be the biggest improvement.”

But the wide receiver position won’t be the Packers’ only upgrade in the speed department. The Packers also made a move at tight end in the offseason, signing street free agent Jared Cook to a one-year, $2.75 million contract with another $900,000 in incentives after he was released Feb. 19 by the Rams.

Cook gives the Packers a big (6-foot-5, 240 pounds) and fast (4.5 in the 40 at the 2009 combine) target over the middle, something near and dear to McCarthy’s heart.

“Let’s be honest, the middle of the field is open now,” McCarthy said at the NFL owners meetings in March. “League rules. Big people running down the middle of the field. I’ll make no secret about it. I think that’s a key to offensive success, whether that’s a big receiver or big tight end or a big man running down the middle of the field, making those safeties cover you. It’s an important part of playing in today’s NFL.”

Cook, who had 39 catches for 481 yards (12.3 yards per catch) last season, cited the opportunity to play with a quarterback the caliber of Rodgers after signing with the Packers, and Rodgers expressed his pleasure with the acquisition on the first day of offseason workouts.

“It was fun to get to talk to him a little bit on the phone before he made it official, and then this morning,” Rodgers said. “I think he’s really excited about the opportunity and we’re excited to have him.”

McCarthy thinks Packers fans will be excited about again having the kind of explosive offense they’d become accustomed to before last season.

“We’ll see how it goes,” he said. “We’ve scored a lot of points around here, so we feel confident we’ll be able to do it again.”

Packers Fans Face Failure and follow him on Twitter @Stucourt.