Cut 5 deep slits in roast. Place a garlic clove in each slit. Pierce roast in several places with a metal meat fork.
Combine in a large resealable plastic baggie: flour, salt, pepper, garlic powder, onion powder and thyme. Rub mixture over entire roast. Cover and refrigerate for 2 hours.
Drizzle 2 tablespoons oil in the bottom of a slow cooker. Place roast in slow cooker. Add chopped onion, sliced mushrooms and bay leaves. Sprinkle beefy-mushroom soup mix over venison mixture.
In a medium bowl, whisk together apple juice or red wine, beef broth, rosemary, Worcestershire sauce and tomato paste. Pour over meat mixture. Add carrots and potatoes.
Put on the cover and turn slow cooker to low Cook 8 to 10 hours.