The lost one of their wide receivers before even taking the field at training camp on Wednesday after veteran Michael Gallup decided to retire after six seasons in the NFL.Gallup, who was expected to compete for the No. 3 wide receiver role Andre Iguodala Jersey against Tre Tucker, was signed back in April with the Raiders in need of more depth, but his retirement basically puts Las Vegas back to square one in that department.If you were shocked by , you aren't alone. On Thursday, Las Vegas general manager Tom Telesco Bam Adebayo Jersey revealed he was completely caught off guard by Gallup's decision to call it quits."I didn't see that one coming at all," Telesco said, per . "That just kind of came up out of the blue. When I talked to him, it seemed like he had a pretty clear vision. He's ready to move on. Gabe Vincent Jersey It's too bad."To compound their i sues at wide receiver at the start of training camp, the Raiders placed wideout Jalen Guyton on the , which is a bad omen considering his injury history. It isn't immediately clear what he's dealing with, though, Precious Achiuwa Jersey and he can be activated at any time.Las Vegas has since signed former "Hard Knocks" star Keelan Do s, but he's hardly a Kelly Olynyk Jersey replacement for either and is just another camp body to fill an offseason roster spot.The Raiders were back on the practice field for their second se sion of training camp on Thursday. They will be back at it once again on Friday.