JACKSONVILLE, Fla. -- Jaguars tackle John Henderson had shortness of breath and was taken to a hospital Tuesday, the second player on the team to have problems with the heat at training camp.

The 6-foot-7, 310-pound Henderson was released from the hospital a few hours later, but it wasn't immediately known when he would be back at practice. Trainer Mike Ryan said his outlook seemed good.

At the end of practice Tuesday morning, Henderson went to the sideline and dropped to his knees. He was quickly surrounded by trainers, who laid him on the ground, stripped off his uniform and sponged him down with ice and cold water.

"This is not a good reflection of how well they're doing in teaching the players and getting them fluids," coach Jack Del Rio said. "We're taking the proper steps, and it's just unfortunate that we've had two guys struggle in the heat like they have."

Del Rio said the team will review everything. One possibility would be installing portable lights in the team's new practice facility and working out at night.

"Every little area or opportunity where we can improve ourselves, we're going to look into it," he said.

The temperature at practice Tuesday was 82. With humidity factored in, it felt like 86.

Conditions were almost identical Sunday, when 310-pound defensive lineman Larry Smith collapsed on the field and was taken to the hospital. He rejoined the team Tuesday but didn't practice outdoors.

Tuesday's practice was in pads, but there wasn't much hitting.

"I'm going to have to take a look at what the big guys are doing in individual practice," Del Rio said. "I know within the body of the practice, we're not overdoing it with our team. We've just happened to have two guys that really succumbed to the heat."

On Sunday, Henderson, 24, went down with cramps and sat out of most of the practice. He later said he didn't eat and drink enough at breakfast. The team's No. 1 draft pick in 2002, Henderson played all 16 games as a rookie, recording 79 tackles and 6.5 sacks.

Other than putting players in pads on the second day of camp, instead of the third, Del Rio's schedule hasn't been much different from former coach Tom Coughlin's.

Gene Upshaw, president of the players' union, said teams know what rules and precautions to take.

"It's very disturbing to see a second player go down there," he said. "But I know Jack Del Rio. I know what type of camp he'd run and how he is about those issues. I have confidence in his ability to do what's right for the players."

On Monday, the widow of Vikings lineman Korey Stringer sued the NFL, accusing the league of fostering a "deadly culture" of abusive exercise that contributed to her husband's death. Stringer, a 335-pound Pro Bowl lineman, collapsed two years ago at the Vikings' training camp.

Since Stringer's death, the NFL has come under scrutiny, not only for practice conditions -- teams often hold two-a-days in 90-degree heat -- but for promoting an unhealthy lifestyle, especially among linemen. The number of linemen weighing over 300 pounds has climbed from about 80 a decade ago to about 300 today.