Keith Law has an Insider-only post up at ESPN on when five teams can realistically expect to compete.
We don't pull much from pay-sites, but Law basically says the Astros can realistically expect to compete in 2018. Law:
Even great drafting won't give them a winning club in 2015-16, and real contention is probably two full cycles away.
In 2018:
Bud Norris will be 34; Brett Wallace, Jordan Schafer, and J.B. Shuck will be 32; J.D. Martinez will be 31; George Springer will be 30; Jose Altuve and Jarred Cosart will be 29; Jordan Lyles and Jonathan Singleton will be 28. Milo Hamilton will be 91. I'll have a 6-year old daughter, who should just be appreciating (and able to remember) the Astros' resurgence.