Boston will send minor league pitcher Stolmy Pimentel and first baseman Jerry Sands to the Pirates, while pitcher Mark Melancon may be included as well, according to ESPN. Two unknown players may be included in the deal.
Originally, the Red Sox reportedly offered up relievers Franklin Morales and Alfredo Aceves for Hanrahan, who has 76 saves over the last two season.
The 31-year-old and two-time All-Star will shore up a Boston bullpen that was 11th in the American League with a 3.88 earned-run average and finished 12th in saves with 35 last season. Last year for Pittsburgh, Hanrahan was 5-2 with a 2.72 ERA; he struck out 67 batters in 59.2 innings.
The Red Sox already have closer Andrew Bailey, but Hanrahan may be insurance as Boston reportedly is not fully convinced Bailey is a long-term solution.
Hanrahan is eligible for arbitration after next season, and made $4.1 million in 2012. Depending on his performance in 2013, he may ask for a significant raise.
Boston acquired Sands from the Los Angeles Dodgers in the August blockbuster trade that cleared the contracts of Adrian Gonzalez, Carl Crawford, and Josh Beckett from their payroll.
Sands spent much of 2012 with Triple-A Albuquerque, appearing in 119 games and hitting .296 with 26 home runs and 107 RBIs. He’s played in 70 major league games, all with the Dodgers, and hit .244 with four home runs and 27 RBIs.
The righty Pimentel went 6-7 in 22 games with Double-A Portland, posting a 4.59 ERA. The 22-year-old Dominican Republic native has spent four years in the minors, and has yet to make his MLB debut.