mschwab@bayareanewsgroup.com

SANTA CLARA -- Earthquakes midfielder Marvin Chavez has a slight left hamstring strain and is doubtful for Saturday's home game against the Chicago Fire, the team announced. Chavez has nine assists, which is tied for the second-most in MLS.

Quakes coach Frank Yallop said he will meet with Chavez on Friday and reassess the situation.

Chavez, who was selected as an inactive MLS All Star this week, suffered the injury in a 2-1 loss in Vancouver on Sunday. He was replaced by Shea Salinas in the 64th minute.

"He'll be OK," Yallop said of Chavez. "If he doesn't play on the weekend we've got a big break coming up, so he should be definitely fine for the next game against Seattle (Aug. 11 in Santa Clara)."

The Earthquakes also announced that forward Steven Lenhart will return to action after being out for three weeks with concussion-like symptoms. Lenhart trained on Thursday and will dress for Saturday's game as a substitute.

"He's been symptom free for the last week, so perfect," Yallop said of Lenhart, who's third on the team in scoring with six goals.

Quakes defender Jed Zayner, who signed with the Quakes on June 20, is expected to start at right back in place of Steven Beitashour, serving a one-game suspension for yellow-card accumulation.

Beitashour played all 90 minutes of the MLS Star Game on Wednesday, helping MLS beat Chelsea 3-2. He has started all 22 games this season for the first-place Quakes (13-5-4). Zayner would make his Quakes' debut. He made 49 appearances combined for the Columbus Crew and D.C. United.