The 34-year-old lock suffered a pectoral injury last weekend during his side's victory over Harlequins in the Aviva Premiership semi-finals.
Despite some concern over Borthwick's fitness, McCall is confident that the veteran will be available for the match in Cardiff.
"He's made some progress actually this week so I suppose we're optimistic but we'll make a decision towards the end of the week," the coach is quoted as saying by Sky Sports News.
"He's got a chance. He hasn't trained yet and there are a few things he's got to do before he's declared fit but we'll make a firm decision on Thursday."
Borthwick confirmed back in November that he will be retiring at the end of the season.