Sounders star Eddie Johnson not allowed to practice Wednesday

TUKWILA — The slumping Sounders can’t afford many more concerns, but a potentially troublesome situation is brewing with Eddie Johnson. The team’s leading scorer wasn’t allowed to practice Wednesday by coach Sigi Schmid.

Not many details were offered but Schmid indicated it was a disciplinary decision rather than anything to do with Johnson’s recovery from a recent groin injury.

Schmid added Johnson’s status is “up in the air.”

The team is scheduled to return to practice Friday ahead of its regular-season finale Sunday against the Los Angeles Galaxy. So how big is this issue as Seattle looks to rebound from a four-game losing streak and gather momentum before the playoffs?

“It’s not an issue at all because we’re focused as a team to do well and to be successful,” Schmid said. “He’s been a big part of our team, so it’s just some things that we’ll work through.”

Johnson, for his part, posted interesting quotes on his Instagram account Tuesday and Wednesday, including one from Malcolm X: “I believe in treating people right, but I’m not going to waste my time trying to treat somebody right who doesn’t know how to return the treatment.”

Another read: “Don’t let your loyalty become slavery. If they don’t appreciate what you bring to the table … let them eat alone.”

Whether the issues are related is impossible to say, but Johnson was visibly and vocally upset as he stormed out of practice Tuesday, and the 29-year-old has been no stranger to controversy in his two seasons with the Sounders.

Johnson has garnered attention for altercations with teammates, opponents and fans, some of which have resulted in punishment from the Sounders and/or MLS. Earlier this season, he performed an infamous “Pay me!” celebration after scoring a goal in Columbus.

On the other hand, Johnson has been the team’s top scorer the past two years, setting a franchise record with 14 goals in 2012 and adding nine more this season in limited time (injuries and duty with the U.S. national team have forced him to miss nearly 40 percent of the season).

The season might be over for Steve Zakuani. The midfielder has been dealing with pain stemming from sports-hernia surgery earlier this year.

The issues trace back to a broken leg he suffered early in 2011, and he had a setback in his recovery earlier this month after a game at Portland.

“Steve Zakuani hasn’t really trained since … saying that the injury is just such that he doesn’t feel he’s going to be able to come back this season,” said Schmid, who added the team would talk about it in more detail later in the day Wednesday.