Joel Hanrahan will be part of the closer mix in Boston. (Getty Images)

While we've known for several days that closer Joel Hanrahan was on his way from Pittsburgh to Boston, the trade has at last been finalized.

As for the particulars, Hanrahan and infielder Brock Holt are headed to the Red Sox, while outfielder Jerry Sands and right-handers Stolmy Pimentel and Mark Melancon will go to the Pirates.

"While acknowledging that trading Joel Hanrahan was a difficult decision," explained Pirates GM Neal Huntington in a statement, "we are pleased that the direct result will be the addition of three players who will very likely impact our major league club this season, plus a pitcher who will add to our deep and talented pitching-prospect base."

Hanrahan told the AP that he "got excited" when he learned of the trade. "Obviously, the Red Sox have a great history and tradition and it's a huge sports city," he said.

The 31-year-old Hanrahan is coming off a season in which he posted a 2.72 ERA and saved 36 games. However, as previously noted in this space, there's reason to be concerned about Hanrahan going forward. The 24-year-old Holt, meanwhile, batted .292/.329/.354 in 72 plate appearances last season. In parts of four minor-league seasons, the ninth-rounder out of Rice has a slash line of .317/.381/.427. He's capable of playing short and second.

On the Pittsburgh side of things, we profiled Sands and Pimentel in our original report. Melancon, 27, has a 4.07 ERA in 157 relief innings at the highest level.

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