As for the other, lesser names involved, reliever Fernando Salas is headed to the Angels, and minor-league outfielder Randal Grichuk also goes to the Cardinals.
The 26-year-old Bourjos is a career .251/.306/.398 hitter (98 OPS+) across parts of four major-league seasons. In 2013, Bourjos hit .274/.333/.377 in 55 games (he missed significant time because of a wrist fracture).
Bourjos's best tool, however, is his speed. On the bases, he's stolen 41 bags in 54 attempts and tallied 18 career triples in 354 games, and he also grades out as an elite defensive center fielder. Given the defensive question marks in the St. Louis outfield -- Jon Jay is not an adequate defensive center fielder, and they're also challenged at the corners with Matt Holliday and (most likely) Allen Craig -- Bourjos's fielding excellence will be important to the Cardinals in 2014.
Grichuk, age 22 and the former 24th overall pick of the 2009 draft, owns a career batting line of .284/.324/.497 across five minor-league seasons. Last season for Double-A Arkansas, Grichuk totaled 22 homers and 27 doubles in 542 plate appearances. Obviously, the Cardinals were drawn to his power potential.
On the Angels' side, Freese, 30, is coming off a 2013 season in which he batted .262/.340/.381 (101 ERA+). In 2012, though, Freese authored an OPS+ of 129 and hit 20 homers in 144 games. Freese has battled lower leg problems in the past, and last season he was limited by a back injury. Freese was of course named MVP of the 2011 NLCS and World Series.
As for Salas, the 28-year-old right-handed reliever has pitched to a 3.42 ERA (111 ERA+), 1.20 WHIP and 2.70 K/BB across parts of four major-league seasons. He functioned as the Cardinals' closer for part of the 2011 season.
As a direct consequence of this trade, the Angels will almost certainly return Mike Trout to center field.