The Australian - impressive since joining the club in the close-season - was on the receiving end of a controversial tackle from home player Anthony Grant in the first half of the 3-1 loss with the challenge infuriating Stendel.
To crown a difficult night, the German was sent to the stands after tempers flared on the touchline in the closing minutes in Shropshire.
On Dougall’s injury, Stendel said: “It is a torn ligament (injury). He cannot play in the next month.
“It is a similar injury to Ryan Hedges and Zeki Fryers.”
Cauley Woodrow may be involved at the weekend, but it is more likely that he will be in the frame for the home game with Southend United on Saturday week.
The striker has yet to make his debut after joining the Oakwell outfit due to a muscle injury.
Zeki Fryers and Lloyd Isgrove also remain on the sidelines - despite edging closer to a return to the fray.