Jammer was shaken up and stayed down for a few minutes after the helmet-to-helmet collision. Weddle limped off after somehow spraining his left ankle.
"It was a pretty good collision," coach Norv Turner said.
Probably the most violent of camp so far.
Weddle came in full speed when he thought he could intercept a pass from Philip Rivers to Chris Chambers.
"I thought I was going to catch the ball and the last thing I remember was seeing his face and then getting up," Weddle said. "I knew I was OK until I stood up and I couldn't feel my legs. So it's like, 'That kind of hurts.'
"I was just worried about him. He was on the ground for a while. So that's the last thing you want. I couldn't forgive myself if something bad happened."
Weddle still wasn't sure how he sprained his ankle. "Something had to have hit me from the outside because it's just up top," he said.
Jammer sat at his locker for a long time after practice.
"I'm good," he said.
Also Thursday, inside linebacker Kevin Burnett left the field with cramps, and first-round draft pick Larry English, an outside linebacker, missed his fourth straight practice with a hamstring injury.
"It's no big deal. It's feeling a lot better," said English, who hopes to be back by the weekend.
Guard Louis Vasquez, the team's third-round draft pick, had his left foot in a boot but Turner wouldn't elaborate on his injury.
"I don't want to go there," Turner said. "We'll be here all day for every single one."
Defensive end Jacques Cesaire also was sidelined, with a calf injury.
"There's a variety of things why guys weren't able to practice today," Turner said. "I don't think we have anything of a serious nature right now."
The Chargers also signed free agent cornerback Antonio Smith.
Copyright 2009 The Associated Press.