ST. JOSEPH, Mo. - The Kansas City Chiefs are facing a potentially devastating loss on defence, even though training camp doesn't begin for veterans until this weekend.

Pro Bowl defensive tackle Dontari Poe will miss camp and likely part of the season after undergoing surgery last week on a herniated disc. The injury initially occurred during the Chiefs' voluntary off-season program, but Poe aggravated it during a workout at home on July 8.

Poe had surgery to remove the disc on July 15.

"He's not doing a whole lot of rehab or treatment. He's just resting," Chiefs trainer Rick Burkholder said Tuesday as rookies and select veterans reported to training camp. "I've told the coaches we won't talk about any more activity with Dontari until we get out of training camp."

Poe is expected to report with the rest of veterans Friday, but he will spend his time with Burkholder and the training staff rather than on the practice field.

Coach Andy Reid said Jaye Howard will be first in line for repetitions, but veteran Mike DeVito and sixth-round pick Rakeem Nunez-Roches could compete for time.

Asked whether he expects Poe back for the season opener Sept. 13, Reid replied: "I think he stands a reasonable chance the early part of the season, whether it's the beginning or somewhere early in the season for his return. You just have to see, see how he recovers.

"It's a positive thing," Reid insisted, "and it's something he needed to get done, as opposed to have that other deal antagonize him throughout the season."

The two-time Pro Bowl selection is coming off arguably the best season of his three-year career. Poe had six sacks despite facing constant double teams, and he was invaluable in slowing down the running game, something that plagued Kansas City all season.

The Chiefs at least have reasonable depth at his position.

Howard started 10 of the 16 games he played in a year ago, and DeVito is returning from a torn Achilles tendon that sidelined him in Week 1. Nunez-Roches is a raw prospect out of Southern Miss, but his size and athleticism made him a favourite among coaches this summer.

Yet replacing Poe is a 6-foot-3, 346-pound task. His bulk and the physical demands of his position combined with the nature of the injury make any return uncertain.

"He'll have extensive rehab and treatment," Burkholder acknowledged.

The news put a damper on what has been an upbeat off-season for the Chiefs.

After barely missing the playoffs a year ago, they upgraded their offence by signing wide receiver Jeremy Maclin in free agency. They also return Pro Bowl linebacker Derrick Johnson from a season-ending injury, and signed All-Pro linebacker Justin Houston to new contract.

Then there was the news late Tuesday that safety Eric Berry, who missed much of last season after he was diagnosed with lymphoma, had been cleared to return to practice. It remains to be seen how quickly he'll get up to speed, but Berry planned to attend practice on Wednesday.

"He's kept himself in good shape, believe it or not," Reid said earlier in the day, before Berry had been cleared. "He's done a really good job there."

___

Online: AP NFL website: www.pro32.ap.org and www.twitter.com/AP_NFL