He wouldn't agree.
"I don't believe I've done enough," Cobb said Sunday, "and I think that's on me."
Cobb's comments came a day after Nelson signed a four-year, $39 million contract extension.
Cobb, 23, is entering the final season of the rookie contract he signed in 2011 after the Packers picked him in the second round. He had a breakout season in 2012, when he caught 80 passes for 954 yards and eight touchdowns.
Last season, he was on pace for more than 90 catches and 1,200 yards until he sustained a fractured tibia against the Baltimore Ravens on Oct. 13 when safety Matt Elam hit him in the leg. Cobb missed the next 10 games but returned for the regular-season finale against the Chicago Bears and caught a 48-yard touchdown pass on fourth down with 38 seconds left that won the game and gave the Packers the NFC North title.
"I got injured in a way that there was nothing I could do about it," Cobb said. "I think my job is just to come out here every day, do what I'm supposed to, continue to work hard, and hopefully my time will come."
Cobb said he was not aware of any contract talks between his agent Jimmy Sexton and the Packers.
"My heart's in Green Bay; I love Green Bay," Cobb said. "The three years I've been here have been unbelievable. But I understand the business side of it. I've been here to see things happen in my room alone with Donald [Driver] and Greg [Jennings] and James [Jones]. So I know the business, I understand that. So I'm trying to focus on day-to-day and handling what I can and letting the business side of it, letting my agent handle that and let it go that way."