NAPA -- Stefen Wisniewski missed all of the Raiders' offseason training programs, having undergone shoulder surgery.And since the Raiders' first offensive series against Dallas in each team's exhibition opener, Wisniewski has been sidelined by a strained calf.Not exactly what you need from a guy making the transition to center from left guard, right?"He needs to get the reps," coach Dennis Allen said Tuesday of Wisniewski. "It's football and you don't just show up and play, so every day he's not out here he's a little bit farther behind."But he's been keeping up mentally as far as taking the mental reps and in the meetings, but it's hard to replace those physical reps you get here and in games."In his place at center, practice squad refugee Alex Parsons has excelled and all-but-solidified his place on the Raiders' 53-man roster."Offseason was awesome," Parsons said. "The fact that you get he reps and you're going against the two tough guys, obviously, Tommy Kelly and (Richard) Seymour. The fact that you get the reps, you can have your system down."Parsons said he dropped 18 pounds from the end of last season, which is also helping his play. And appearance."I look better in white," Parsons joked. "I don't have that gut. There's a huge difference conditioning-wise as well."Getting all of Wisniewski's reps of late does not hurt, either."He's done well," Allen said. "He's done well. As a matter of fact, he was competing the whole time and we were impressed with what we've seen out of him. Again, we've got a next-man-up philosophy. If Wiz is ready to go, great. If not, then it's next-man-up and Alex will go in there and play and we expect to see results from him, and he's given us every indication that we'll see that."Allen said with Jacoby Ford and his sore left foot -- he was still walking around in a boot Tuesday after hurting it Friday -- unlikely to play and Denarius Moore still nursing a sore hamstring, undrafted rookie Rod Streater would start at one of the receiver spots against Detroit on Saturday."Again, next-man-up philosophy," Allen said. "He's the next man up on the list. We put him up and go out and do your job."Streater has 13 catches for 109 yards in two preseason games."He's been forced into the starting role and because of injuries, it doesn't seem like he's earned it," said quarterback Carson Palmer. "But he can play with the best of them."Free safety Michael Huff returned to the Raiders after being excused last weekend to attend the birth of his daughter, Madeline Rae."She was 6 (pounds), 2 (ounces)," Huff said. "She was born (at) 4:24. That's a great number, the 24. I made sure I pulled her right out at 24. I was looking at the clock."For those of you needing a program, yes, Huff wears No. 24.