Motherwell keeper Trevor Carson faces a minimum of three months out with a knee injury.Scans have shown the Northern Irish international suffered a meniscus tear in the weekend win over Ross County.The 32-year-old has now been told he is unlikely to be back fit until January at the earliest.It is a devastating blow for Carson as he has had to battle back from deep vein thrombosis, which threatened his career.He lost the top slot at Motherwell and was out for almost 18 months before he regained