The 29-year-old missed his side's 2-2 draw with Aston Villa after suffering a calf injury during the international break.
Ridgewell had played all of West Brom's Premier League matches prior to Monday night's encounter at the Hawthorns, and could return for the match at St James' Park.
"Liam injured his calf in training the week before (the Villa match)," Clarke told the club's official website.
"It's a calf strain and I'm not sure how long he'll be out for.
"He's started jogging again so he's got an outside chance of being ready for the weekend."
After the visit to Newcastle, West Brom host Manchester City and Norwich City in the following seven days and Clarke is keen to ensure he manages Ridgewell's injury sensibly.
"We've got plenty of games coming up so we have to be careful it doesn't become a long-term injury," added the Scot.
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