'"Those are two quality veterans who bring so much to the table from an experience standpoint and a leadership standpoint,'' said Raiders head coach Bill Callahan. ''Their presence is invaluable.''
Robbins has been Oakland's starting center since 1996 and was considered one of the top centers in the AFC before tearing the anterior cruciate ligament in his right knee during the second week of the regular season last year.
The injury left Robbins a bystander as the Raiders offense, once so dominant on the ground, changed direction and took to the air with a great deal of success. But with Callahan having replaced Jon Gruden as head coach, Oakland is looking to get back to its roots with the running game.
Though back-up center Adam Treu played better than expected and filled in admirably during Robbins' absence, the Raiders couldn't wait to get Robbins back into the lineup. He has been working out at the Raiders' facilities since getting the OK from doctors and has been taking part in light, non-contact drills.
In the voluntary mini-camp, Robbins was back in his usual position in the middle of Oakland's starting offensive line. Little has changed since he left -- Gruden is no longer calling the plays and Frank Middleton has replaced long-time left guard Steve Wisniewski -- so it was easy for the 29-year-old to slip back into the mix.
''It was really exciting just to be able to go out and stretch with those guys,'' said Robbins. ''I'm approaching it just like a (normal) mini-camp. I'm just trying to get some cohesiveness with Frank over there and get back into things with the rest of the guys.''
Armstrong, who ruptured the Achilles tendon in his right foot a week after Robbins injured his knee, is also eager to be back on the field. Like Robbins, Armstrong is being limited by the Raiders in what he can do at this point but all roads are pointing to him being ready to go full speed once training camp opens in late July.
''I'm real pleased with the way things are going,'' said Armstrong. ''I'm not at 100 percent yet but I don't even think about it. I run, I cut and I don't feel any pain.''
That's encouraging news for Oakland's defense, which got only 12 sacks from its starting defensive ends last season.