Jamie Roberts knocks out Blair Cowan with big tackle in Six Nations thriller

Wales' tight 27-23 victory over Scotland in Cardiff in the 6 Nations was arguably the pick of the action from the weekend. It was also a brutally physical encounter, and one which took its toll on a number of players. Among the casualties was Scotland flanker Blair Cowan, who came off after a head-on-head collision with Welsh centre Jamie Roberts. And while it was deemed a perfectly legal hit from Roberts, who walked away unscathed, Cowan had to leave the field to undergo a Head Injury Assessment (HIA) to determine whether any concussion occurred. It also came on the weekend when a new docume…