Baseball America had Houston last in its organizational rankings before the season.
The Arizona Diamondbacks also were ranked low in Baseball America's list (No. 28) but could be a possibility for Oklahoma City if they decided to leave Reno.
Arizona's affiliate had been in Tucson for the first 11 seasons of the big league team's existence, but the Tucson franchise moved to Reno last year in the final year of the club's player development contract. So the Diamondbacks figure to at least be open to the possibility of change.
Toronto long had a similar cozy relationship with its Triple-A affiliate in Syracuse. But the Jays were left scrambling when Syracuse decided to go with the Washington Nationals two years ago because of Toronto's history of struggling teams at the Triple-A level.
The Blue Jays wound up going with Las Vegas, by far the longest distance separating a major league club with its top affiliate.
The first day a PDC can be signed with a team is Sept. 16, and deals must be made in two- or four-year increments.