O'Bryant swatting any misconceptions

A 7-foot center leaves a Bay Area team to join the Celtics after being called either lazy or unmotivated. That is what happened in 1980, when the Celtics acquired Robert Parish from the Warriors, and again this year as Patrick O'Bryant joined the Celtics as a free agent.

O'Bryant might not win as many NBA titles as Parish. He might not even become the Celtics' starting center. But, so far, O'Bryant has been disproving the negative labels in leading the Celtics in field goal percentage (.632), blocked shots (1.7), and rebounds (6.3) during the exhibition season.

O'Bryant started the first three games but is projected as a backup for Kendrick Perkins (shoulder), who is expected to return for tomorrow's game against Cleveland in Pittsburgh.

"Patrick is a quick learner," coach Doc Rivers said after the Celtics' 90-89 win over Houston in Manchester, N.H., Saturday night. "I thought he was terrific down low a couple times, as well. The first post we gave him he took a fadeaway jump shot over a 6-9 guy, then the next two times he got it deep in the paint, so that was good."

Rivers's motivational tactics have worked with O'Bryant. During a 96-94 win over Cleveland in Providence Friday night, O'Bryant was replaced in the third quarter.

"I took him out because I didn't like the way he was playing," Rivers said. "He clearly gives the first effort and you can see him thinking about the second and third effort. He needs to know the culture we're trying to create here and that you need to be into that to play here."

By the fourth quarter, O'Bryant was plugged into the Celtics' work ethic.

"I love playing basketball," O'Bryant said. "Getting a chance to play, it's hard not to have fun, even if you are out there working hard [and] you feel like you are dying from exhaustion."

O'Bryant was clearly disappointed by his Golden State experience, as he played in only 40 games in two seasons.

O'Bryant is influenced by a San Franciscan who made his name in Boston long before Parish, as illustrated by a play in the final quarter of the Celtics' win over Cleveland. O'Bryant swatted away a Vernon Hamilton drive but, instead of sending the ball toward Federal Hill, he was careful to make sure it remained in play.

"That's Bill Russell right there," O'Bryant said. "I read an article on him once and he said anybody can throw a blocked shot seven rows up and scream. But then it's their ball and maybe an in-bounds play is their best play. If you keep it in play and, as long as the guards know what's going on, it should fall in their hands."

Asked if he preferred making a good defensive play or an offensive play, O'Bryant said, "I prefer a blocked shot. There are not many people who pride themselves on being a shot-blocker. I want to be able to come in the game and make a difference. When I walk off the court, people will know Pat was just here, he helped us get a better lead, he shut down someone, or whatever it is I needed to do."

...

Rookie Bill Walker tangled with Houston's Tracy McGrady in the first half Saturday. McGrady was whistled for a flagrant foul, and both received technicals.

"I told him, 'Don't back down, but don't be stupid,' " Rivers said of Walker. "Bill will get under a lot of people's skins because he plays so physical and cuts so hard. People don't like it, but it's what's going to make him a good player."

Said Kevin Garnett, "[Walker] is definitely not the guy to back down, but, more importantly, he kept his composure."

Frank Dell'Apa can be reached at f_dellapa@globe.com.