Yesterday, Jim Salisbury of CSNPhilly.com reported that free agent closer Jonathan Papelbon had agreed to terms on a 4-year, $50 million deal with the Phillies.

After a reported 4-year, $44 million deal with last year’s closer, Ryan Madson, fell through earlier this week, Phillies GM Ruben Amaro, Jr. acted quickly, acquiring the player who many analysts considered to be the best closer on the free agent market this offseason.

The 30-year-old closer was a constant force in the Boston Red Sox’s bullpen over the last six-plus seasons, racking up a franchise-record 219 saves and never finishing lower than eighth in the AL in saves. Throughout his career in Boston, Papelbon posted a 2.33 ERA in 396 appearances.

Papelbon also made the AL All-Star squad each year from 2006-2009.

Papelbon had a great 2011 campaign, setting a career high in strikeouts while walking just 10 batters, his lowest total since the 2008 season. He also became the first player in Major League history to have at least 30 saves in each of his first six full seasons in the big leagues. The Phillies hope that Papelbon’s success carries over into the National League.

The 2007 DHL Delivery Man of the Year brings both experience and success to Philly; he has proven time and time again that he can be trusted with the game on the line. Assuming the Phillies continue their success and once again advance to the postseason in the 2012 season, Papelbon should have no problem controlling his nerves; he has had the privilege of throwing the final pitch of a World Series, finishing off Seth Smith with a strikeout and clinching a title for Boston.

One thing the Phillies hope Papelbon can improve on however, is not blowing saves. It is not a huge problem if a closer blows a few saves in a year, especially when the team wins 100+ games and is backed by a historically great rotation. However, Papelbon has blown his fair share of saves in the past, 29 to be exact. His 88.3% save conversion rate is nothing to “balk” at, though. His career high for blown saves in a season is eight, coming in his 2010 season. This past season, he reduced that total to just three blown saves. The Phillies hope that the closer can hover around that total, and perhaps even lower it in the years to come.

In the end, this is a signing that the Phillies will have to evaluate when Papelbon’s contract expires at the end of the 2015 season. There is no telling which Papelbon the Phillies will get over the next four years, the rookie Papelbon with a 0.92 ERA or maybe the 2010 Papelbon that finished with a 3.90 ERA to go along with 7 losses and 8 blown saves, or maybe something in between. Will Papelbon be a bust? Was he overpaid? Or will he help bring the Commissioner’s Trophy back to Philadelphia? Only time will tell if the fifty-million dollar closer is a good fit in the Phillies’ bullpen.