Fluminense's former Brazil international Marcelo has been handed a three-match ban by CONMEBOL after his lunge at Argentinos Juniors' Luciano Sanchez left the defender with a horrific injury in a Copa Libertadores clash in Buenos Aires last week.

The 35-year-old left-back will also have to pay a $6 000 fine, South American soccer's governing body added on Thursday.

Marcelo was dribbling towards Sanchez when his leading foot went past the ball and caught the Argentine high on the shin with force. The Argentinos player's leg buckled underneath him at a shocking angle, leaving him lying in agony on the pitch.

Sanchez left the pitch on a stretcher with what was later confirmed to be a fracture that the team doctor said he had "never seen before".

The ex-Real Madrid player was sent off in tears following the incident in the 1-1 draw in the last 16, first leg.

"Today I had a very difficult moment on the pitch," Marcelo posted on Instagram hours later.

"I unintentionally injured a fellow player. I want to wish him the best possible recovery. All the strength in the world."

Marcelo has already served the first game of his three-match ban by missing the second leg where the Brazilian side won 2-0.