Walker came to terms with the most lucrative deal at $5.75 million. But of the six arbitration-eligible players reaching agreements with the Bucs, Alvarez was regarded the most likely to reach a hearing in front of a three-member panel, and for good reason: A solid case as the National League's co-leader with 36 home runs.
General manager Neal Huntington avoided that potential showdown with an agreement for $4.25 million, a raise of more than 600 percent over Alvarez's 2013 salary of $700,000.
Walker received a bump from $3.3 million in his second go at arbitration.
Sanchez ($2.3 million), Melancon ($2.595 million) and Mazzaro ($950,000) brought to 16 the number of signed players on the Pirates' 40-man roster, representing a total commitment of $71 million. The club had ended the 2013 season with a payroll of $74.6 million.
Sanchez batted .254 last season, with seven homers and 36 RBIs in 136 games, and is a frontrunner to be the Bucs' primary first baseman in 2014. The six-year veteran did most of his damage against southpaw pitching -- batting .333 in 102 at-bats against lefties -- but Pirates leadership feels strongly he could be a productive everyday player, although it remains on the lookout for a lefty bat to platoon him with.
Walker is considered a key to the Bucs' offensive improvement in the coming season. Fighting through multiple minor injuries, the switch-hitter slumped to a .251 average in 2013, when he drove in a career-low 53 runs.
Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. He can also be found on Twitter @Tom_Singer. This story was not subject to the approval of Major League Baseball or its clubs.