On April 1, 1987, Dal Maxvill sent outfielder Andy Van Slyke, catcher Mike LaValliere, and a minor league pitcher by the name of Mike Dunne to the Pittsburgh Pirates in exchange for three time All Star catcher Tony Pena. Van Slyke thought it was an April Fools joke, while Pena openly wept when he was informed of the deal.
In hindsight the deal might not have been the best ever made in the history of the Cardinals organization, as Van Slyke lived up to his true potential in Pittsburgh. At the time of the trade Van Slyke was 26-years-old and had played 521 games, hitting .259, with 41 homers. He had fell short of expectations, but many thought he had the tools to become an All Star caliber player, which he did in Pittsburgh, as he went to the mid summer classic three times representing the Buccos.
Pena had a rough year in '87, just three games into his stay with the Cardinals he broke his thumb, and went onto hit just .214, however, he found his stride near the end of the season and helped the Cardinals win the National League East. Pena then went onto hit .381 in the NLCS, which was key in helping the Cardinals reach the World Series.
Pena caught more than 140 games in each of the next two seasons that he wore the Birds on the Bat. In 1989 he returned to the All Star game as one of the best defensive catchers in all of baseball. Following that '89 campaign Pena was granted his release from the club and inked a deal with the Boston Red Sox. Meanwhile in the Steel City, Van Slyke developed into a star. He wore the Pirates uniform until the end of the '94 season. In his 8 years in Pittsburgh, Van Slyke hit .283 and knocked 117 home runs out of the yard. Comparatively, Pena hit just .253 in his three years with the Birds and parked 19 balls in the seats.
The other players involved: Mike Dunne and Mike LaValliere had some success. Dunne won 13 games for the Pirates during the '87 season, but arm issues kept him from finding great success. LaValliere and Van Slyke helped the Pirates reach the NLCS for three consecutive years from '90-'92. However, that is as far as they got. LaVallier spent 7 seasons with the Pirates and hit .278 in that time. While this trade might not have been the best one ever made for the Birds it was a trade that wrote another chapter in the rich history of the organization.
If you would like to look over the numbers of each of the ballplayers involved in the deal you can check them out here.
Tony Pena: http://www.baseball-reference.com/players/p/penato01.shtml
Andy Van Slyke: http://www.baseball-reference.com/players/v/vanslan01.shtml
Mike LaValliere: http://www.baseball-reference.com/players/l/lavalmi01.shtml
Mike Dunne: http://www.baseball-reference.com/players/d/dunnemi01.shtml