Collison schooled Mullens about the NBA's hand-checking rules in the post, teaching the rookie that a forearm to the back of an offensive player is allowed but an extended arm with an open palm is a foul.

"That's something I didn't know until he told me," Mullens said.

On one hand, Mullens is no different from any other rookie entering the league and learning the rules. On the other hand, that small point of emphasis illustrates how far Mullens has to go.

His journey begins tonight, as the Thunder opens its preseason schedule at Memphis at 7 p.m. Thunder coach Scott Brooks said he didn't know how much Mullens would play tonight against the Grizzlies. But during a month-long exhibition season, newcomers like Mullens typically get the bulk of the minutes.

And tonight's matchup could pit the only two centers drafted in the first round against each other, provided Mullens does see action. Hasheem Thabeet, the 7-foot-3 inch center out of Connecticut who was taken with the No. 2 overall pick, could give Mullens a tough test early.

"It's going to be real nice," Mullens said. "It's our first preseason game, my first NBA game. We'll see what happens. I'm just going to go out there and play my hardest and we'll see."

Mullens, the 7-footer from Ohio State, met up with Thabeet in the Thunder's opening game in the NBA Summer League in Las Vegas. It was a forgettable performance from a team standpoint and for both players. Mullens scored five points and failed to pull down a rebound in 13 minutes. Thabeet scored nine points with two rebounds in 20 minutes. The Thunder lost 86-57.

Mullens, who once was projected as a lottery pick, downplayed the potential matchup and said his individual goals are much more basic and personal.

"Just to get in the game and get the pace of it and the physicality of it," Mullens said. "And just stay healthy. I know we're going to be doing a lot of traveling, so I've got to get used to taking a plane back and forth."

Brooks and general manager Sam Presti have both sung Mullens' praises since the June draft. But both coach and GM generally have followed up statements about Mullens' physical gifts with the caveat that his development will take time.

Mullens said he's made strides over the past week of training camp, improving his conditioning through two-a-days while spending time learning the NBA game from coaches and veterans.

"You've just got to be patient with it," Mullens said of the mental aspect of adjusting to a new league. "These coaches are really good with patience and they just told everybody that if you forget something, speak up. We're not going to yell at you. But they are throwing in a lot of information and a lot of plays."

Mullens said he hasn't had an issue keeping up with the speed of the game or the pace at which Brooks is installing offensive and defensive sets. And Brooks said Mullens has impressed the coaching staff.

"I like what he's been doing in practice," Brooks said. "He's showing why he belongs in this league because he runs well, he can block shots and he's picking up the offensive system that we're putting in place. It's going to take time. Guys have to learn the league, they have to learn the system. And I think all that's going to come together the more days we're around him."

Mullens is willing to be patient.

"I'm looking forward to it," Mullens said of tonight's debut. "And it doesn't matter how many minutes I get. I'm just happy to be here. This is what I worked for my whole life."

Thunder at Grizzlies

Time: 7 p.m.

Where: FedEx Forum, Memphis, Tenn.

TV: None

Radio: WWLS 98.1-FM, 640-AM.

Three things to know

→This is the preseason opener for the Thunder .

→Guard Thabo Sefolosha and forward Nick Collison will not play due to injuries.

→Grizzlies guard Allen Iverson is out with a hamstring injury.

Probable starters

Thunder

Pos. Player Ht. G Russell Westbrook 6-3 G Kyle Weaver 6-6 F Kevin Durant 6-9 F Jeff Green 6-9 C Nenad Krstic 7-0

Grizzlies

Pos. Player Ht. G Mike Conley 6-1 G O.J. Mayo 6-4 F Rudy Gay 6-8 F Zach Randolph 6-9 C Marc Gasol 7-1