Rival #2: Seattle Mariners
This inter-division rivalry has the potential to be something. Preferably this something is good. In fact, this could be the season in which this rivalry takes off.
Of course, you may remember when then-Mariners manager Lloyd McClendon in 2014 called Astros starter Dallas Keuchel an “average pitcher“, which earned, fairly or not, the ire of the Astros fan base.
Since the 2014 season, the Astros are now 23-15 against the Mariners. On the flip side, the Astros finished behind Seattle in the standings last season despite their success.
Like the Angels and Athletics, there is very little past history to base this rivalary on. And they appear to be two franchises heading in different directions in the long-term. Seattle has a talented major league roster yet their farm system isn’t looked upon highly. Houston, on the other hand, possesses one of the deeper minor league farm systems in baseball today. So if this rivalary is going to take off, it would likley need to occur in the short-term future.