Carp, 27, hit .296 (64-for-216) with 18 doubles, two triples, nine home runs, 43 RBI, and 22 walks in a career-high 86 games in 2013. It was his first campaign with the Red Sox after being acquired from the Seattle Mariners last February. The left-handed batter reached base safely in 40 of his 56 starts between left field (31), first base (23), and right field (2). His .523 slugging percentage ranked eighth among American Leaguers with at least 200 plate appearances last season. He also appeared in six postseason games during Boston's run to the World Series title. Originally signed by the New York Mets as a ninth-round selection in the 2004 June Draft, Carp has hit .267 (203-for-761) with 46 doubles, four triples, 27 homers, and 114 RBI in parts of five major league seasons with the Mariners (2009-12) and Red Sox (2013).
Herrera is entering his first season with the Red Sox after being acquired from the Colorado Rockies in exchange for left-handed pitcher Franklin Morales and minor league right-hander Chris Martin on December 18, 2013. The 29-year-old posted a career-high .292 average (57-for-195) with seven doubles, two triples, one home run, and 16 RBI in 81 games with Colorado in 2013 while appearing defensively at shortstop (42 games), second base (22), third base (5), and left field (2). Signed by the Rockies as an international free agent in 2002, the switch-hitter has batted .265 (261-for-984) with 28 doubles, seven triples, eight homers, 66 RBI, 87 walks, and 14 stolen bases in 375 career big league games over parts of five seasons with the Rockies (2008, 2010-13).
Tazawa went 5-4 with a 3.16 ERA (24 ER/68.1 IP), 72 strikeouts and a team-high 25 holds for the Red Sox last year, his first full season in the major leagues. The 27-year-old right-hander walked just 12 batters and ranked among AL relief leaders in strikeout-to-walk ratio (T-3rd, 6.0) and fewest walks allowed per nine innings (5th, 1.6). He appeared in 13 of Boston's 16 postseason games, allowing just one run in 7.1 innings for a 1.23 ERA. Tazawa is 8-8 with a 3.45 ERA (54 ER/140.2 IP) and 134 strikeouts compared to just 27 walks in 117 outings (four starts) over four major league seasons with the Red Sox (2009, 2011-13).
With today's agreements, left-handed pitcher Andrew Miller is the only remaining unsigned Red Sox player eligible for salary arbitration.