ENGLEWOOD, Colo. - Denver Broncos All-Pro linebacker Von Miller insisted Monday he did nothing wrong in the face of reports he could miss four games for violating the NFL's drug policy.

"I know I did nothing wrong. I'm sure this'll be resolved fairly," Miller tweeted, saying he had seen the reports and adding he was disappointed the Broncos have to open training camp with this news hanging over them.

George Atallah, spokesman for the NFLPA, said the players union was working with Miller on an appeal, adding via Twitter: "I can also confirm that Von's case does not involve the Steroids and Related Substances Policy."

That suggests Miller's case could involve recreational drugs instead.

Without Miller, the second overall pick in the 2011 draft, the Broncos defense would be missing its best pass rusher for its first four games - against Baltimore, the New York Giants, Oakland and Philadelphia.

RG3 tweets he's cleared

WASHINGTON - Quarterback Robert Griffin III passed a test toward his goal of playing in Week 1, getting the go-ahead from team doctors days before the Washington Redskins open training camp.

"Doctors cleared me to practice. Coach is going to ease me in," tweeted Griffin, who is hoping to be under center when the Redskins open the regular season against the Philadelphia Eagles on Sept. 9, just eight months after he had reconstructive surgery on his right knee.

The Redskins had no comment on Griffin's tweet.

HGH study underway

The NFL and players union are talking again about getting a test in place for human growth hormone as early as this season.

An email from the NFL Players Association indicates that the league and the NFLPA have jointly hired a doctor to conduct a study on NFL players to determine a good threshold for a positive HGH test. The email told players the study requires them to have blood drawn during physicals when training camp begins but samples are only for the study.

The labor agreement that ended the NFL lockout in 2011 requires the league gain union approval before testing players for HGH. The union says it favors testing, but has reservations about the appeals process.

Scott still with Jags

The Jacksonville Jaguars are carrying four quarterbacks into training camp, including former UA Wildcat Matt Scott.

The Jaguars waived rookie QB Jordan Rodgers from Vanderbilt on Monday. The move leaves Jacksonville with QBs Blaine Gabbert, Chad Henne, Mike Kafka and rookie Scott in camp.

Extra points

• Cornerback Eric Wright failed his physical with the 49ers, nullifying a trade to bring him to San Francisco from Tampa Bay. The Bucs then released Wright.

• New England Patriots coach Bill Belichick is scheduled to speak to reporters on Wednesday - his first availability since tight end Aaron Hernandez was arrested on murder charges.

• The Houston Texans signed first-round pick receiver DeAndre Hopkins on Monday.