COSTA MESA, Calif. -- Michael Gallup, who signed a one-year contract worth as much as $3 million with the Las Vegas Raiders on April 30 and was expected to compete for the team's No. 3 receiver spot, instead retired Tuesday, the day before the Raiders' first training camp practice.

Gallup, 28, participated in OTAs and minicamp for the Raiders this offseason. A six-year NFL veteran, he caught 266 passes for 3,744 yards and 21 touchdowns with the Dallas Cowboys.

The Raiders also announced that starting left tackle Kolton Miller, a six-year starter who missed a career-high four games last season and underwent offseason shoulder surgery, would begin camp on the physically unable to perform list.

Also placed on the PUP list by Las Vegas were receiver Jalen Guyton, a five-year veteran with 71 career catches for 1,112 yards and 7 TDs for the Los Angeles Chargers who signed a one-year, $1.9 million contract with the Raiders on May 6; linebacker Darien Butler; guard Jake Johanning; and second-round draft pick Jackson Powers-Johnson, who is expected to compete for playing time at left guard. Powers-Johnson suffered a shoulder injury in OTAs, but a source with knowledge of the situation said that injury is not the reason he is beginning his first training camp on the PUP list.