Castro, 26, was an American League All-Star last season and posted a .276 (120x435) batting average with 18 home runs and 56 RBI in 120 games. He had one of the greatest offensive seasons by a catcher in Astros history, setting single-season club records by a catcher in doubles (35), home runs (18), runs scored (63), extra-base hits (54), slugging (.485), multi-hit games (33) and OPS (.835). Castro led all AL catchers in slugging (min. 450 PAs) and finished second in OPS. Castro was a first-time, arbitration-eligible player and has played in parts of three seasons with the Astros (2010, 2012-13).
Guzman, 29, was acquired by Houston from San Diego on Dec. 18, 2013, in exchange for infielder Ryan Jackson. Guzman played in 126 games for the Padres in 2013, collecting 17 doubles, nine home runs and 35 RBI. He started at four different positions last season, including 33 games at first base, 25 in left field, three in right field and two at third base. He was especially effective as a pinch-hitter, hitting three home runs and leading the Majors with 14 RBI in that role. Like Castro, Guzman was a first-time, arbitration-eligible player.