Greg Olson and Jon Gruden coached together for just one season in Tampa Bay in 2008. Yet Olson says his “learning curve greatly increased” in his year as Gruden’s quarterbacks coach. It’s the main reason Olson left the Rams to become Gruden’s offensive coordinator with the Raiders last week. And it’s similar to the effect Olson expects Gruden to have on quarterback Derek Carr. “It’s the first time Derek’s going to have an offensive head coach that’s got a quarterback background that will be hands-on with him on a day-to-day basis,” Olson said on a conference call Wednesday.