The Philadelphia Eagles' offense may be fun to watch, but some NFL players have doubts they can continue running coach Chip Kelly's up-tempo attack every week.
Veterans know staying healthy is a prerequisite for success in the NFL. And Green Bay receiver Jordy Nelson, for one, saw signs of trouble during Philadelphia's 33-27 win against the Washington Redskins on Monday night.
"Just watching the game from the outside, you could already see [Michael] Vick struggling getting off the field every once in a while," Nelson said. "The guys are a little older in the league, so they could start breaking down.
"It's going to be a trial and error, and it will be up to their organization and coaching staff to monitor that and see what they do all week in practice to counterbalance it all."
Nelson also made it a point to mention that the NFL season is longer and teams have fewer players than those at the college level, where Kelly made his name and popularized his "point-a-minute" offense with the Oregon Ducks.
Reaction from around the league, however, agreed that the offense was fun to watch, that the Eagles had the right weapons and that they played at a fast pace and scored a lot of points.
The Eagles ran 30 plays in the first quarter and gained 196 yards. In the second half, the Eagles managed just 121 yards and five first downs. Overall, they ran 77 plays, gained 443 yards and had 26 first downs. Running back LeSean McCoy rushed for 184 yards on 31 carries.
"I'd have to see them do it for a whole game first, but they did it for the half and it was impressive," Pittsburgh Steelers safety Ryan Clark said. "I think they have the right pieces and parts for it."
Houston Texans left tackle Duane Brown said it can work, "as long as the linemen are in shape. If they're able to keep that up, they're able to put a lot of pressure on defenses. Washington definitely looked gassed out there."
"You got to be able to evolve with the game," Dansby said. "If you don't, you'll get left behind."
"It's crazy," Wagner said. "They ran 50-something plays in the first half and only 20-something in the second half. It shows you they can't keep that type of pace."
ESPN.com's Rob Demovsky, Scott Brown, Tania Ganguli, Josh Weinfuss and Terry Blount contributed to this report.