The wide receiver from Georgia Tech signed a six-year contract just in time for an 8:30 a.m. practice, the Lions' first public workout.
The 500 fans in attendance cheered when they realized Johnson was on the field. Applause followed every catch he made in the two-hour practice.
"I thought today went pretty well," Johnson said. "I made some mistakes, but I was able to retain a lot of what I picked up in (offseason team activities)."
And it made sense he was working with the starters right away.
"I wasn't surprised. I was expecting to be out there with the first team," Johnson said. "That's why they picked me at No. 2."
Johnson caught 78 passes for 1,202 yards and 15 touchdowns during his All-America junior season, and he won the Biletnikoff Award, given to the nation's top college receiver.
Johnson is expected to team with Roy Williams and Mike Furrey to give the Lions a triple-threat receiving corps.
Marinelli expects Johnson to affect Detroit's rushing attack.
"When we have those three men on the field, and especially when we add Shaun McDonald as a fourth receiver, it is going to force defenses to spread themselves wide," he said. "That's going to open up a lot of room for Tatum Bell or Kevin Jones."
Linebacker Warrick Holdman was released from the hospital Friday, 24 hours after being treated for a spinal cord concussion following a collision with a teammate at training camp.
The Broncos didn't say when Holdman, who spent the night at Sky Ridge Medical Center, would be able to practice again.
Holdman was injured Thursday when he tried to tackle running back Mike Bell, who lowered his left shoulder and struck the 243-pound linebacker in the crown of his helmet. Holdman crumpled to the grass and temporarily lost feeling in his extremities, although he could move his arms and legs by the time he was taken off the field to an ambulance.
Right offensive tackle Ryan Tucker was suspended for the first four games of the season for violating the NFL's policy on anabolic steroids and related substances.
Tucker admitted taking a banned substance, saying he did so while being treated for a mental disorder that limited him to nine games last season.
Tucker can practice with the Browns through training camp and the preseason. However, he cannot be with the team during his suspension, which begins Sept. 1 and runs through Oct. 1. He is not appealing the ban.
Free agent tight end Erik Jensen signed a one-year deal, adding depth to the Bengals' most depleted position. Cincinnati has lost three reserve tight ends to injury since training camp began.
Seven-time Pro Bowl defensive end Michael Strahan probably will release a statement on his holdout over the weekend, according to his agent. Strahan, 35, failed to report to training camp a week ago, hours after agent Tony Agnone stunned the Giants by telling them that Strahan was considering retirement after 14 NFL seasons.
There has been speculation that Strahan, who was scheduled to earn $4 million this season, is holding out in an effort to renegotiate his contract after losing a bitter divorce case that cost him $15.3 million.
Reserve defensive tackle John McCargo is out indefinitely after straining an abdominal muscle during a training camp practice. Buffalo coach Dick Jauron couldn't estimate how much practice time McCargo will miss, saying only "We hope it won't be long." It's not clear when McCargo was hurt, but he continued watching practice from the sideline with his stomach heavily wrapped.
Left tackle Luke Petitgout returned to practice in a limited fashion Friday afternoon after sitting out Tuesday, Wednesday, Thursday and Friday morning. Petitgout, signed as a free agent in March, started nine games for the New York Giants before breaking a leg against Chicago on Nov. 12 and missing the remainder of last season.
Defensive end Simeon Rice's tour of NFL teams brought him to Tennessee's headquarters Friday, and he was gone after a few hours.
Rice, who also took a physical with the New York Giants on Wednesday, is expected to meet with other teams.
Tampa Bay waived Rice last week because of an injured shoulder. His 121 sacks are second only to New York Giants defensive end Michael Strahan's 132 1/2 among active players.
Linebacker Chris Draft, who has been suffering from an asthma-like condition, practiced Friday. Draft, who signed as a free agent after making 107 tackles for Carolina last season, had been out since early in his first workout on July 27. He was cleared to practice after being examined Thursday.