Luke Walton sits out against Portland

Lakers forward Luke Walton sat out Sunday’s game against Portland because of a sore right foot and will see foot specialist Kenneth Jung today to determine the extent of his injury.

Walton is believed to be experiencing sesamoiditis, a condition in which there is irritation in the sesamoids, which are small bones bundled with tendons that run to the big toe.

The condition typically requires a to-be-determined rest period but not surgery.

Walton had started 11 consecutive games at small forward and was averaging 5.8 points, 3.1 rebounds and 3.1 assists since moving into the starting lineup.

Walton’s foot hurt before Friday’s game against Utah and it worsened after Saturday’s practice.

“Every time I step on it, it hurts. Every time I extend my foot, it hurts,” Walton said. “It’s something I tried to push through, but the more I ran on it, the worse it felt. It’s like there’s a burning rod being stuck in it.”

Trevor Ariza replaced Walton on Sunday and had four points, five rebounds and two assists in 32 minutes. His defense on point guard Steve Blake helped turn the game the Lakers’ way in the second half.

Ariza, however, was a reluctant starter.

“He asked me not to put him out there with the starters . . . which is understandable,” Coach Phil Jackson said. “He has a role on the second unit and they look for him. There’s more offensive opportunities in that group. But we needed that [defense] tonight.”

Despite Walton’s unclear status, the Lakers haven’t been in a rush to fill out a roster already short-handed because Jordan Farmar will be out about six more weeks (torn knee cartilage).

Jackson continues to monitor the minutes accrued by Derek Fisher, who logged 33 against Portland.

“When I look down in the box score and I see that Fish has played 40 minutes again, that’s usually when we say that’s too many minutes for him at this particular time of the season,” Jackson said.

Odom evolution

Lamar Odom is in his 10th NBA season, but Jackson says the 29-year-old is still making some adjustments.

Odom typically plays on the wing after playing primarily at power forward the last few seasons. He sometimes gets the team into its offensive sets, a role he held last season only after grabbing a rebound and pushing the ball down court.

“He’s had to change hats a couple times during the course of the game,” Jackson said. “I think he’s gotten more comfortable. I really like the fact he got aggressive halfway through that [recent] road trip. After the Miami fracas and Orlando situation, he started becoming aggressive again as a player.

“We do want him to get involved in the offense and not just be a spectator . . . and [not] just let Pau [Gasol] and Kobe [Bryant] have their opportunities out there,” Jackson said Sunday.

Odom is averaging 8.7 points, 6.3 rebounds and 2.3 assists.

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mike.bresnahn@latimes.com