Reading your point on the matter it's you who seems biased mate.
-Because Barker played well in the past he should be given a debut now? If that is the merit to pick your players, we would be shambles.
-Because Garcia is better in a 5-a-side at training? Just reread this and I hope you see how stupid or childish that sounds.
Pellegrini wasn't picked as our manager to be an old sentimental fool with an obvious weakness to the local lads. My opinion is that Garcia was being picked because at that particular moment Pellegrini thought the team could do with a change and he looked what player or position needed it most. Any other descision you could state the man is not perfect for the job, not at the level we are aiming at. You can state we didn't play our strongest 11, but Pellegrini has a bigger picture to beware of.
Barker, as any other academyproduct that makes it to the senior squad, needs to take the chance and learn as much as possible, not taking anything for granted and prove to the manager either way you are ready to make the step. Barker was great last season, but his development stalled early 2015. Evenso he made the step up to the senior squad as did Garcia who is in fact two years younger.