This is another weird one because Ken Caminiti had actually established himself a pretty good player for the Astros by his eighth season in the big leagues. The 1994 season was the best of his career with a .283/.352/.495 line with 18 homers and he got named to his first All-Star Game. However, the Astros were again looking to trim their payroll and they sent Caminiti to the Padres in a gigantic 12 player deal that brought back Derek Bell among others.
However, Caminiti's 1994 season was simply foreshadowing of things to come. He would win National League MVP in 1996 in San Diego during a torrid three season stretch in the mid 90's where he slashed .307/.393/.549 with 92 homers and won three Gold Gloves.
Caminiti would at least return to Houston after his time with the Padres and played pretty well for a couple of years before eventually hanging it up in 2001. It is hard to be too hard on Houston here as Caminiti had a number of substance abuse problems and was an admitted steroid abuser during his prime.
Finally, we come to a name that younger Astros fans may not even be aware of. John Mayberry was the sixth overall pick in the 1967 MLB Draft and would debut in the big leagues as a 19 year old in 1968. Mayberry would only find token playing time with Houston over the next four seasons and he did not play particularly well when he did play with a .191/.284/.342 line in an Astros uniform. Given his struggles, the Astros traded Mayberry during the offseason after the 1971 season to the Royals.
The regret from that deal would be swift as Mayberry broke out in his first season with the Royals with 25 home runs and a .900 OPS. Mayberry would go on to play six seasons with Kansas City including the 1975 season where he finished second in MVP voting while slashing a .291/.416/.547 line with 34 homers. He would go on to play in the big leagues for the Blue Jays and Yankees before retiring after the 1982 season.