In many ways, Bulls center Robin Lopez is a walking contradiction. The crazy hair and the framed picture of Britney Spears he keeps in his locker scream outside the box. Ten years in the NBA, however, have instilled some old-school values that he doesn’t take lightly. Lopez understands the Bulls are in a rebuild, and youth will be served on a nightly basis, but there’s a side of him that misses the good ol’ days. “There’s something to be said for earning minutes,’’ Lopez said of young guys playing right away. “It kind of builds character. It’s just not going to work out perfectly all the time, but I’m a proponent of that.’’ That’s because the NBA raised Lopez that way. Selected by the Suns with the 15th overall pick in the 2008 draft, he played behind Shaquille O’Neal, earning 10.2 minutes per game his rookie season and learning his craft by watching.