Well, so was Campo. Zimmer, hired in 94,worked under him on the defense when Campo was DC. Campo had some good years as DC, top 5 in points twice. Zimmer took over in 2000 and the defense went from 5th in points and 9th in yards to 23rd. Duce Staley on opening day 200 yards rushing. 3 weeks later, Charlie Garner SF 201 yards. Week 14, Warrick Dunn 210 yards. So I was wrong in my initial post. He allowed 3 200 yard rushers.
It took a few years but Zimmer got the defense back in the top 5 in 2003 under Parcells. But then tanked again the following year and until he left was never a top 10 defense again. He's a classic JAG.