The Thunder and 66ers use the same terminology offensively and defensively, which helps with player transitions within the franchise.
"He's got the right attitude," 66ers coach Nate Tibbetts said of Mullen. "That's the way he needs to continue to approach it. He brought a professional approach to practice every day, coming in early, working on his game. He really bought into being in Tulsa. With us, he got to feel comfortable and gain some confidence. He's got a beautiful shot and he's not limited. He's very comfortable facing up.
"He's still a young guy. He's still trying to figure out who he is. If I were to tell you what he can and cannot do, in three years it might be way different. If he can focus on defense and rebounding, it's really going to help him."
We'll learn Thursday night if the Thunder adds more centers to its roster, but Mullens welcomes the competition.
"He's got a great personality and he's really upbeat about what's going on," Tibbetts said. "As a basketball player, you've always got guys trying to take your job."