OWINGS MILLS, Md. -- Baltimore Ravens coach John Harbaugh doesn't think that the bodies of rookies are tough enough to handle the rigors of NFL practices like they were in the past.
Harbaugh's comments come after rookie tight ends Hayden Hurst and Mark Andrews missed their combined fifth practice of training camp because of soft-tissue injuries.
"One thing I've noticed: Guys coming out of college aren't as callused up as they used to be," Harbaugh said. "We used to practice twice a day in full pads. And those players know -- I'm talking to you out there who know, who've played in the National Football League or played in college 10, 15 years ago -- [that] it's not even close to the same thing.
"There's a certain type of 'in shape,' certain type of football fitness, certain type of callusness -- muscles, joints, tendons, ligaments -- that kind of toughen up. They callus up a little bit, and you can practice all day and run all day. Then our guys coming in right now, most of them don't have that."
The injuries to Hurst and Andrews -- two of Baltimore's first four picks in this year's draft -- have left the team thin at tight end. Nick Boyle and Maxx Williams, who are both in their fourth seasons, have had to take nearly every rep.
"They're not batting an eye. Why? Because they're callused up, because they know how to practice, because their bodies are just tougher," Harbaugh said. "There's a physical toughness to it. They're mentally tough. But you have to practice football to be able to practice football the right way."