The Nationals on Wednesday claimed Class AA third baseman Carlos Rivero on waivers from the Philadelphia Phillies, a significant move in that Rivero was added to the Nationals’ 40-man roster (which now stands at 37 players) and must stay there (or clear waivers) if the team wants to keep him.

Rivero, a 23-year-old Venezuelan, had his best season as a professional in 2011, hitting .270/.326/.440 in 136 games, mostly at Class AA Reading.

He spent the first five years of his professional career in the Indians’ organization, playing mostly at shortstop. After claiming him on waivers in 2010, the Phillies switched him to third base. He was on the Phillies’ 40-man roster this winter.

It is possible the Nationals will consider Rivero as a backup to Ryan Zimmerman in 2012, a role mostly filled in 2011 by Jerry Hairston before his trade to Milwaukee.


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