The Toronto Maple Leafs signed unrestricted free agent David Clarkson last July to improve forward depth and bolster team toughness .
David Clarkson returns to Leafs lineup Friday against the Columbus Blue Jackets .
The Leafs     signed unrestricted David Clarkson   David Clarkson last July to improve forward depth and bolster team toughness .
David Clarkson returns to Leafs lineup Friday against the Columbus Blue Jackets .