Of course with the huge hole at the center position the Pistons needed a replacement for Ben Wallace. Of course Mohammed will not be a force like Ben Wallace was, it is still a sutible addition for a empty role in the Pistons roster. He signed a 5-year deal with the Pistons, and the final year being a option. He will also be A LOT cheaper then Wallace and be more of an offensive threat. Nazr Mohammed actually had a disappointing year last season for the Spurs, only averaging 6.2 points and 5.2 rebounds. If he can repeat what he did for the Knicks back in the 2004-05 season, he should be a nice fit. Nazr is a physically gifted player, excellent offensive rebounder, very good mobility, and he has improved his offensive game. However, he is injury prone.
Bottom line, the Pistons had to do something in the wake of Ben Wallace's defection to Chicago. You can't compare Nazr Mohammad to Wallace, but at least Detroit found themselves a big center.