The 32-year-old Hill is in the midst of a down season, hitting just .251/.285/.381 with a 84 OPS+ and -0.5 WAR. However, he has been one of the better (albeit inconsistent) second basemen in the league over the past eight years, with three 5.0+ WAR seasons and a 103 OPS+ since 2007. He has been especially strong offensively over the past couple years, hitting .298/.359/.501 with a 130 OPS+ and 6.2 WAR in 243 games during the 2012 and 2013 seasons, missing nearly half the season last year. Hill is making $11 million this year, and is owed $12 million annually over the next two years.
If truly available, Hill should have a sizable market due to the large number of contending teams in need of second base help. The Giants, Braves, Orioles, and Athletics all make sense as possible landing spots.
Meanwhile, Arizona plans to hold onto the 30-year-old Prado, prizing him due to his versatility and leadership qualities. The Diamondbacks seem to view Prado as part of their core going forward, along with first baseman Paul Goldschmidt, shortstop Chris Owings, catcher Miguel Montero, and left-hander Wade Miley.
Like Hill, Prado is locked up through the 2016 season, though he will make $2 million less at $24 million total over the next two years on what remains of the four-year, $40 million extension Prado agreed to shortly after being acquired from the Atlanta Braves in the Justin Upton trade. Prado is hitting .274/.319/.369 with a 91 OPS+ and 1.4 WAR this year. He has averaged 3.4 WAR per season since becoming a regular in 2009, and has spent time at every position except pitcher, catcher, and center field.
Per Heyman, the Diamondbacks could also deal relievers Oliver Perez, Addison Reed, and Brad Ziegler, though Arizona seems to be more inclined to deal Reed than the other two.