Martin Perez is probably your best pitching prospect and is MLB ready as well. He actually already has 2 years of MLB service and you can delay this by holding him back in the minors for a year or two. Focus on training his per nines and he should be a solid a number 2-3 pitcher in the rotation until he hits free agency.
Texas has two good young catcher prospects in Tomas Telis and Jorge Alfaro. Telis is a switch hitter, while Alfaro bats from the right side. They are similar, defensively, however Alfaro does have a secondary position at first base. Once Chirinos is eligible for free agency, these 2 catchers should be in their prime. Make sure that you add them to your 40 man rotation within your first 3 years, because they will be eligible for the rule 5 draft. I recommend training in both in the weight room as their defense is already pretty decent and will be solid once they are MLB ready.
Chi Chi Gonzalez, Luke Jackson, and Anthony Ranaudo are all pitching prospects with B potential. I would be patient with these guys as they can be MLB ready in 3-4 years. Be sure to add them to your 40 man roster to avoid other teams snagging them via rule 5 draft and focus training on their per nine attributes (Pitching Coach Sessions).
Projects that you may want to ship off via trade
Michael Choice, Ryan Rua, Nomar Mazara, Lewis Brinson, and Nick Williams are all B potential prospects you can use to acquire more ready MLB players via trade. These guys are all in their 50’s or low 60’s and will be too old once they hit their prime. It isn’t really worth keeping them in your farm system to progress either, since they are not much of a help on your 40 man roster and they will eventually be snagged via rule 5 draft. Get value when you can out of these players and try to find deals for them immediately! For instance I was able to trade Choice, Rua and Brinson for players like Alex Guerrero, Wilsin Rosario, Jon Jay, Pedro Alvarez, Ben Revere, etc. These guys are all still fairly young and can be an impact on your 25 man roster for the next several years.
Players to consider for trade bait
Adrian Beltre is the obvious fit here. He is 36 years old with a 1 year left on his contract and he is owed 21 million. Eventually, Gallo can take over or you can move Profar to 3b if you prefer to have Gallo at 1b/DH. Again, you should definitely trade him unless you are in contention. Put him on the trade block and see what your options are in trade finder. Focus on getting pitching prospects in return that will be ready in 2-3 years! If you happen to keep Beltre the entire year then you will have the option to tender him a qualifying offer for 10.5 million. If he declines then Texas will be granted a compensation pick (additional pick after the 1st round and before the 2nd round). This could be an alternative to trading him as you will allow Gallo to work on his fielding for another year before moving him to 3b for Texas or you can get an additional draft pick!
Beltre will still be very productive for the next few years, despite his degression, and he usually wants a 2-3 year deal in Free Agency. One interesting trade I found was Adam Jones and Darren O’ Day for Beltre. This would free up 15.2 million and add a lot more youth to Texas. These are all things to consider and is, arguably, the most important decision you will make your first year with Texas.