Portland Thorns coach Paul Riley went over the injury list on Tuesday after practice, alternately encouraged and concerned.

On defender Kat Williamson, who is recovering from a mild concussion: She's "clean as a whistle," going through the protocol, Riley said. "Hopefully she'll get through. She's a big part for us, you know."

On defender Rachel Van Hollebeke, who has been dealing with hamstring issues: The situation "is a bit tricky," Riley said. He's "not going to risk Rachel in any way. It's a long season ahead of us. If it takes another week, we'll take another week."

On forward Alex Morgan, slowed by a knee injury: "Alex won't be playing this weekend. She's still resting," Riley said. "I wish she was playing. ... We'll miss her, but she needs to take time off now, with the World Cup coming."

That means the Thorns (2-0-0, 6 points) are thin, especially on defense, as they prepare to play their first road game of the season on Saturday, when they take on the Chicago Red Stars (1-0-0, 3 points) at Village of Lisle-Benedictine University Sports Complex.

Hollebeke and Williamson were on the field at Providence Park during Tuesday's practice, working off to the side with a trainer. Alex Morgan was absent from the field.

Riley said he'll look at changing formations, especially along the back as he evaluates Van Hollebeke and Williamson.

Chicago is coming off a 3-2 home win against Seattle and poses a variety of challenges -- the Red Stars have speed and can score a variety of ways and the defense is stingy.

"They don't give many goals up," Riley said. "They're well organized and they're just really difficult to play against, especially (when we're) away from home."

-- Molly Blue