Fox and the Rockets/Astros couldn't wait for the conditions that would free them from having to use KNWS. KTXH badly needs some boost to bring in viewers that NEVER watch that station, much less know it exists. As for KPRC carrying the Astros, it's all about $$$$$$'s for Drayton McClain and the Stros. If KPRC is willing to pony up for a few weekend Astros games as a promotional platform for their station, the Astros will take it. They are more loyal to money than to Fox. Their deal with Fox is in the third or fourth year of a 10 year deal and it's for a minimum number of games. Any games over that minimum number costs extra and the Astros have the right to sell those games to anyone. Although the ratings would not amount to much it would be a great move for KPRC. They have died the past couple of years due to poor NBC programming and their own shotty news operation. If the Astros have another bad year, it might be a waste of money. If the Astros are competitive the move to carry weekend games is a no lose proposition with them. Weekend prime, especially in the summer and Sat nights is a wasteland with few ratings carried by anyone. Whereas the Astros might not get KPRC much in the ratings dept, it might get them new viewers that will be new eyeballs for their news promos. Fox in Houston would love to get those weekend games for KTXH as well, but if it means spending extra bucks, they'll never do it. Their expense budgets are so thin to begin with there is never any wiggle room for such opportuniities during their budget year (July-June). If such an expense is not in their budgets when they are presented the prior spring, they really never have any kind of opportunistic spending bucks available for programming such as this during the year.
As for the Rockets deal, FSN owns the rights to all the games and can place those games on any other broadcast station in the market. It's obvious that they would use their own station (KTXH) for that. With My20 a quasi network at best with marginal programming, Fox corporate gave the ok for the station to carry some Rockets games. It's rare the Fox corporate allows local sports franchises to preempt network fare, but I guess they view MyNetwork as preemptible now, plus the Rockets are a favorite to compete for a title this year.