The Lakers’ decision to trade backup center Chris Mihm today to the Memphis Grizzlies invited more questions than it answered. First and foremost, does this mean GM Mitch Kupchak will make another move before the league’s trade deadline Thursday at noon? With starting center Andrew Bynum out until at least April, the Lakers are suddenly short on 7-footers. What’s more, who will serve as Pau Gasol’s backup with Bynum sidelined and Mihm in Memphis? The short answer is Josh Powell, a burly backup forward/center.