Andrew Bynum has bone bruise

SACRAMENTO, Calif. -- Los Angeles Lakers center Andrew Bynum, who hyperextended his right knee Tuesday against the San Antonio Spurs, had a MRI on Wednesday that showed he has a bone bruise in the knee.

The injury is not deemed to be serious according to the team and the Lakers expect him to be back this weekend for the start of the playoffs.

"We'll have to see how he plays, how he reacts to this," Lakers coach Phil Jackson said. "We're optimistic. Obviously we got a reading that sounds good, but it's still getting him on the floor playing at the level he left that will make us a really good team. So we have to bring that back and hopefully he can play [in Game 1] and contribute."

He also said it would be possible to sit Bynum out for Game 1, but, "it depends upon the schedule."

Bynum was hurt during the second quarter against the Spurs when
he fell awkwardly to the court after stepping on DeJuan Blair's
foot while getting back on defense. Bynum's knees are a constant
concern for the Lakers, but he walked to the locker room under his
own power and told Jackson he didn't believe the injury
was serious.

"He allows us to be the dominant team we're capable of being,"
guard Derek Fisher said. "It's hard to think about not having him
for any significant length of time. It was tough to see. He's so
important to what we do, so to even think for a second that he
might be out, the impact that would have on him after all of his
work, it's tough to deal with in the moment."

Bynum is averaging 11.5 points, 9.5 rebounds and nearly two blocked shots in 54 games this season and has been the key to the Lakers' second-half turnaround, serving as the unofficial defensive captain in the middle. The 23-year-old's
imposing size alongside fellow 7-footer Pau Gasol is the Lakers'
biggest asset outside Kobe Bryant, and Bynum is in the midst of a
remarkable defensive season.

But knee injuries have been the only constant in the career of
Bynum, the youngest player ever drafted by an NBA team when the
Lakers selected the 17-year-old six years ago with the 10th overall

The Lakers also have played more games than any other NBA team
over the past four years after making three straight NBA Finals,
and the cumulative toll has been obvious in every player -- even
Bryant, whose litany of minor injuries in the past two seasons
currently includes a sprained left ankle.

"We always think positively, optimistically," said Gasol,
who's playing through a bone bruise in his right knee. "Andrew is
willing to sacrifice himself to be out there, and he'll play and
fight through anything."

Bynum missed the first 24 games of this season while recovering
from offseason surgery to repair a torn meniscus in his knee, and a
bone bruise in his left knee forced him to miss a game in February.

He also had surgery on his left knee in 2008 after dislocating
his kneecap, keeping him out for 47 regular-season games and the
first of Los Angeles' three straight runs to the NBA Finals. The
Lakers lost to Boston in the 2008 Finals without Bynum, but they've
won the past two championship series with Bynum in uniform.

Bynum partially tore the meniscus in his right knee late last
season, but postponed surgery until summer to start all 23 playoff
games in the Lakers' championship run - and to make a trip to the
World Cup in South Africa.

Bynum's absence means the Lakers will be further undermanned Wednesday as they try to hang on to the No. 2 seed in the West in their regular-season finale against the Sacramento Kings. Two other players did not make the trip because of injury and illness.

Lakers forward Matt Barnes also had an MRI on his sore right knee, which was surgically repaired in January and caused him to miss 26 games.

Results of Barnes' MRI showed no new damage.

Barnes, who has averaged 6.7 points and 4.3 rebounds in 19.2 minutes per game on the season, said he felt a "sharp pain" in the back of his right knee Monday, keeping him out of the Spurs game, but he is also expected to be ready when the Lakers begin the playoffs.

The third Lakers player not to make the trip, backup point guard Steve Blake, is out indefinitely with the chicken pox.

"It could be a situation where it's over a week [that he's out], so we have to be careful about it," Jackson said.

The NBA has not announced when the Lakers' opening game will be yet; however, they have typically started the postseason with a Sunday afternoon game in years past.

In need of reinforcements for Wednesday's game, the Lakers recalled rookie forward Derrick Caracter and signed guard Trey Johnson from Bakersfield of the NBA D-League.

Caracter has appeared in 40 games with the Lakers this season, averaging 2.0 points and 1.1 rebounds. He also has spent two stints in Bakersfield.

Johnson spent the preseason with the Lakers before his fourth D-League season, ranking second in the league with 25.5 points per game. He also spent seven games with the Toronto Raptors.

Dave McMenamin covers the Lakers for ESPNLosAngeles.com. Information from The Associated Press was used in this report.