Byrd, 34, owns a .278 career average (1,040-for-3,735) with 215 doubles, 27 triples, 81 home runs, 438 RBI, 516 runs, 274 walks and 49 stolen bases in 1,069 Major League games over 11 seasons with the Phillies (2002-05), Nationals (2005-06), Rangers (2007-09) and Cubs (2010-12). A 2010 All-Star, he has appeared at all three outfield positions with 810 games in center, 142 in left and 109 in right. He has started in center field in all 13 of his games with Chicago this season and reached base safely in six of those contests, going 3-for-43 with two RBI, three walks and a run scored. Originally selected by Philadelphia in the 10th round of the 1999 First-Year Player Draft, Byrd has hit at a .287 clip (698-for-2,433) in 661 games since the start of the 2007 campaign.
Bowden, 25, was designated for assignment by Boston on April 15 after posting a 3.00 ERA (1 ER/3.0 IP) in two relief appearances with the club this season. Selected by the Red Sox in the supplemental round (47th overall) of the 2005 First-Year Player Draft, the right-hander has made 39 career Major League appearances (two starts) over the last five seasons since 2008, going 2-2 with a 5.61 ERA (37 ER/59.1 IP) and 48 strikeouts compared to 23 walks.
Spears, 26, has appeared in four games with the Red Sox since being selected to the Major League roster on April 15 and gone 0-for-4. He played in eight games with Triple-A Pawtucket to begin the season, going 6-for-26 (.231) with two RBI, five runs and three walks. Spears made his Major League debut with Boston last September, appearing in three games with the club. Originally selected by Baltimore in the fifth round of the 2003 First-Year Player Draft, he has hit .272 (900-for-3,305) with 171 doubles, 43 triples, 55 home runs, 377 RBI, 536 runs, 427 walks and 85 stolen bases in 966 minor league games in the Orioles, Cubs and Red Sox organizations.