Report: Nationals making progress on trade for Phillies' Papelbon

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The Washington Nationals are reportedly making strides in their pursuit to acquire Jonathan Papelbon from the Philadelphia Phillies.

The six-time All-Star has stated he will only approve a trade to teams where he will assume the closer role, according to Ken Rosenthal of FOX Sports. That could prove difficult with Drew Storen holding down a 1.73 ERA and 29 saves in 31 opportunities for the Nationals this season.

Jim Salisbury of CSNPhilly.com also reported Tuesday that a source familiar with the situation has said "Papelbon will be traded" ahead of the deadline.

However, Papelbon is a perfect 17-for-17 in save opportunities this season and is sporting his lowest ERA (1.59) since 2006. The 34-year-old has been vocal in recent weeks in his desire to be moved to a contender before the July 31 deadline.

The Nationals are among many teams targeting the veteran reliever with the Toronto Blue Jays and Chicago Cubs also reported to be coveting his services.

Rosenthal reported earlier this week that the Nationals were hesitant about taking on Papelbon's contract and would be open to Philadelphia taking the majority of the pitcher's remaining salary for this season.

It is unclear how advanced trade talks are at this stage or what kind of return the Phillies are expecting in exchange for their closer's services.