Kansas City quarterback Brodie Croyle throws during the first day of training camp. Second-year man Croyle and veteran Damon Huard will compete for the starting job.

River Falls, Wis. ? With one Pro Bowl running back sitting out in a contract dispute and a former Pro Bowl running back making a surprise return, the Kansas City Chiefs on Friday opened what could be their most interesting training camp in many years.

Subplots and story lines abound. Questions about Herm Edwards’ quest to rebuild one of the league’s oldest rosters are about as thick as the piney woods that ring this picturesque college town in western Wisconsin, where the Chiefs have been coming for 17 years to escape the energy-sapping Midwestern heat.

Many of the Chiefs’ marquee players of the recent past are gone, including quarterback Trent Green, guard Will Shields and return specialist Dante Hall.

Who will replace Green? Edwards insists the competition will be fair between second-year man Brodie Croyle and 34-year-old career backup Damon Huard, who played well in eight games after Green got hurt last year.

Many observers see Croyle as the quarterback of the future and believe it will be his job to lose.

Who will replace place kicker Lawrence Tynes, who was sent packing? That much is known: It will be rookie fifth-round draft choice Justin Medlock. But how effective will he be?

There will be a new kicker, a new long snapper and a new return man to break in, making special teams one of the biggest mysteries as camp gets under way.

The offensive line, long a strong point and a major reason the Chiefs had one of the NFL’s most powerful attacks, must be substantially rebuilt. Left guard Brian Waters and center Casey Wiegmann are the only starters left from the great lines of recent years. Moving over from tackle to take over for Shields is John Welbourn.

By far the most-watched man in camp, however, will be Priest Holmes. Out of football for 21 months since suffering neck and head trauma, Kansas City’s career rushing leader announced this week that he would report to camp on Saturday. His arrival adds a new twist to the situation surrounding Larry Johnson, who is demanding guaranteed money in the $28 million range and will be fined more than $14,000 every day he misses camp.

Will Holmes be in shape? Can he possibly compete at the age of 33 after being out of football since October 2005?

The Chiefs will proceed cautiously and probably put Holmes on the physically unable to perform list and not have him practice right away.

“His history of overcoming the odds are very good, and he’s done that in the past earlier in his career,” Edwards said. “He’s a fantastic football player, a very good football player here, but he hasn’t played in two years, and you have to keep that in mind and make sure you protect him. He understands that we’re pulling for him to do it and we’re going to give him every opportunity to do it.”

Edwards kicked off camp Friday morning by running all 88 players through what he called a “test,” a series of grueling runs designed to pinpoint players who had not kept themselves in shape.

Overall, coaches were pleased.

“It tells me that once they left on the 23rd of June and they were away from our facility, they were doing something,” he said. “They were working out.”

First to be tested were the offensive and defensive linemen.

“You always worry about the big guys,” Edwards said. “But the great thing about pro football players is they don’t want to embarrass themselves.”