OWINGS MILLS, Md. -- Ravens coach John Harbaugh wants the NFL to add a one-week warm-up period before training camps, which he believes would lessen the injuries that occur early on.

Baltimore became the first NFL team to open camp Thursday because the Ravens are participating in this year's Hall of Fame game. Harbaugh is using that extra week to focus on individual drills and conditioning for his older players.

Many of the veteran players practiced for about an hour. Players such as quarterback Joe Flacco, linebacker Terrell Suggs and safety Eric Weddle won't have a full camp practice until Monday.

"Acclimation is very important," Harbaugh said. "If we could get a week instead of two days -- not to push it back so we have a shorter time to get our guys ready for football -- to put in front of training camp where we can get our guys ramped up for the collisions and hard movements, maybe we would avoid some of those first two- to three-day injuries that we get during training camp. That's our goal this year."

Last year the Ravens lost two players -- tight end Crockett Gillmore and cornerback Maurice Canady -- to significant knee injuries on the second day of training camp. The Ravens, who placed 15 players on injured reserve last season, have been looking at ways to reduce injuries.

Other than the Chicago Bears, who play the Ravens in the Hall of Fame game, the rest of the teams don't report until Wednesday.

"It gives us the opportunity, probably over the long haul, to get more work in, but also to spread the work out a little more and give us a little more recovery, which would be beneficial," Harbaugh said.

Wide receiver Michael Crabtree, who is on his third NFL team, appreciates how Harbaugh started camp.

"You have to pace yourself," Crabtree said. "You don't want to come in full speed and you have five weeks until the first game."