Safety Quintin Mikell left the practice about mid-way through after tweaking his knee and rookie wide receiver Riley Cooper did not practice because of a hamstring spasm. "I'm good," Mikell said after practice, warding off concerns. As for the action on the field, Quintin Demps stepped in as the first-team safety alongside rookie Nate Allen once Mikell left the field, and seemed to work well with Allen, offering pointers throughout. - Mike Bell continues to take advantage of his reps with the first team at running back, as he's shown a surprising fluidity in his route running and catching ability. Bell was hit along the sidelines in stride several times during Wednesday's practice on passes from Kevin Kolb. - Mike McGlynn is still getting some reps with the first-team offense at center, but Nick Cole remains the man in the middle. - During seven-on-seven drills, rookie defensive end Daniel Te'o-Nesheim got a few looks in coverage as a linebacker of sorts. It's obviously not the strongest part of his game, but he appears to be a willing learner and is athletic enough to make strides. - Joselio Hanson has been the first-team right cornerback in the base defense all week as Ellis Hobbs continues to sit out team drills. But whenever the defense switches to nickel, Hanson slides back inside and Macho Harris replaces him as the right corner. Dimitri Patterson has also been impressive this week in his stint as the "starting" left cornerback. - Jason Avant was around the ball all day as the Eagles offense seemed to make a point to feature the slot man in the middle of the field, especially against some of the pressure package looks that the faux Cowboys defense presented. - Finally, former Eagles head coach Dick Vermeil was seen on the sidelines observing practice.