The Pirates have acquired pitcher Vin Mazzaro and first baseman Clint Robinson from the Royals for pitchers Luis Rico and Luis Santos. The team has also acquired pitcher Zach Stewart from the Red Sox for a player to be named later. 

Mazzaro, 26, has spent time as both a starter and reliever with the Athletics and the Royals. He threw 44 innings with Kansas City last season, compiling a 5.73 ERA and a 4.30 FIP. 

Robinson, 27, made his major league debut last season, receiving four plate appearances with the Royals. He hit .292/.393/.452 in 570 plate appearances in Triple-A, but was old for the league. 

Luis Santos started seven games for the Pirates' Dominican Summer League team. He was fairly effective, tossing 30 2/3 innings with a 2.64 ERA and a 2.22 FIP. Santos is just 21-years-old, and is still a while away from making an impact in the majors. 

At 17, Rico is the youngest player in the deal. He threw 26 1/3 innings for the team’s Venezuelan Summer League, registering a 3.76 ERA and a 3.92 FIP.

For more on the club’s trade for Zach Stewart, visit the Eye On Baseball blog. 

For more up-to-the-minute news and analysis on the latest rumors from bloggers Chris Cwik, Jack Moore and R.J. White, follow @MLBRumorsCBS.