The Lakers made it official Friday, signing starting center Chris Kaman to a one-season contract worth $3,183,000 for next season. Backup center Robert Sacre signed his new contract Wednesday. It’s for three seasons, with the first two guaranteed. He’s set to make $788,873 next season, then $915,243 in 2014-15 and $981,358 in 2015-16. Of the players on the current roster, only Sacre and point guard Steve Nash are signed beyond next season, giving the Lakers salary-cap flexibility at long last next summer.