West Ham United co-chairman David Sullivan believes Jonathan Calleri can be a key player in his first season with the cub.

The Argentine striker completed his season-long loan move from Deportivo Maldonado on Tuesday and is expected to immediately become one of the East London club's most important attackers according to his new chief.

"He's a top player and was the leading goalscorer this season in the Copa Libertadores, the South American version of the Champions League," Sullivan told the club's official website.

"He is the immediate back up for Argentina who are the number one rated team in the world.

"He showed his quality at the Olympic Games for Argentina this summer and will be another great addition to the squad.

"We have a great track record of signing players from Argentina with Carlos Tevez and Manuel Lanzini becoming big players at West Ham United. It would be great if Jonathan could follow in their footsteps.

"We expect him to be one of our top goalscorers this season."

Calleri, 22, joins West Ham having enjoyed stints with All Boys, Boca Juniors and Sao Paulo.