The Pirates made two minor trades Wednesday, adding options at pitcher and first base in advance of the non-tender deadline, which is Friday.
The Kansas City Royals sent right-hander Vin Mazzaro and first baseman Clint Robinson to the Pirates in exchange for minor league pitchers Luis Rico and Luis Santos. In a separate trade, the Pirates acquired right-hander Zach Stewart from the Boston Red Sox for a player to be named later.
To accommodate the new additions, the Pirates designated first baseman Matt Hague and infielder Yamaico Navarro for assignment. Their 40-man roster is full.
Robinson, 27, was drafted by the Royals in 2007 and made his major league debut this past season. After hitting 23 home runs for Class AAA Omaha in '11, he batted .292 with 13 home runs and a .393 on-base percentage this past season.
"We've seen a guy whose bat and his power and command of the zone intrigues us," Pirates general manager Neal Huntington said. "Just a guy that hasn't had much opportunity because he's had a very good player [Eric Hosmer] in front of him."
Robinson joins Garrett Jones and Gaby Sanchez, who are both eligible for arbitration and must be tendered contracts by midnight Friday, as first-base options. When asked if the new additions would affect arbitration decisions, Huntington said the process will play out itself.
Jones had his best season since '09; Sanchez had a .279 on-base percentage and seven home runs in 326 plate appearances.
Mazzaro made six starts and 12 relief appearances in '12. He allowed 55 hits in 44 innings and walked 19 batters. In 22 appearances, including eight starts at Omaha, Mazzaro had a 3.63 ERA.
Huntington said the Pirates believe Mazzaro's sinker and slider could allow him to earn his way into a late-inning relief role, possibly assuming the role that Jason Grilli would vacate if he isn't re-signed.
Stewart, 26, who joined the Red Sox from the Chicago White Sox in the Kevin Youkilis trade, pitched 352/3 innings in the majors this past season, allowing 14 home runs with an 8.58 ERA.
"We've liked him as a prospect in the past," said Huntington, who noted that Stewart could start or relieve. "We've stayed with him. He's tried to make that transition from prospect to major-league pitcher."
The trades expand the pitching choices before the non-tender deadline. Right-handers Jeff Karstens and Charlie Morton, who is rehabilitating after Tommy John ligament replacement surgery, are eligible for arbitration. Karstens will make in the neighborhood of $3.5 million to $4 million, Morton around $2.75 million.
Rico, who turns 19 today, and Santos, 21, pitched for the Pirates' Dominican Summer League affiliate this season.
NOTES -- According to reports from Fox Sports and CBS Sports, the Pirates have joined the New York Yankees, Seattle Mariners and Texas Rangers in pursuit of free-agent catcher Russell Martin. Huntington declined to comment on the reports. CBS Sports reported that the Pirates could offer Martin, who will be 30 by opening day, a three-year contract worth between $21 million-$25 million. ... The Pirates hired four professional scouts: Ricky Bennett, who spent the past two seasons as the director of pro scouting for Houston; Carlos Berroa, who worked for Miami; Ron Hopkins, who served as a national cross-checker for Baltimore; and John Kosciak, who spent 2012 as an area supervisor with the Astros.
Bill Brink: firstname.lastname@example.org and Twitter: @BrinkPG.