"Shawn Marion has heard speculation about the Dallas Mavericks' various game plans for him this season -- all of which are written in sand so they can be easily changed.No matter the role in which he ends up, Marion plans on doing more things better this season, including resurrecting his 3-point shot.But at the Mavericks' first practice of training camp at SMU, it turns out Marion isn't the only longtime NBA starter who has been approached about perhaps coming off the bench this season."I've talked to both Shawn and Caron [Butler] that one of them could be coming off the bench for the first time in their careers," coach Rick Carlisle said Tuesday. "I want this to be an element of strength that we're playing to."Not that one of those guys is in decline or anything like that. None of it is personal. It's going to be about being the best possible team."Marion has started 805 out of 820 games in his career. While he wants to play a fair share of minutes, this year it's more about getting opportunities when he plays."