He was not created Infante in 1914, but in 1905, when he married Infanta Maria Teresa. Actually, he was created after the marriage was announced. So he married as Infante of Spain. https://www.boe.es/datos/pdfs/BOE//1905/295/A00277-00277.pdf
Before being an Infante of Spain, he was not a member of the Spanish Royal Family. Only the King, Queen, Prince of Asturias and Infantes were considered members of the SRF. A special status had children of Infante Alfonso of Bavaria and Infante Carlos of Borbon (children of his second marriage).
Was this royal (a male-line great-grandson of King Ludwig I) always regarded as a SPANISH PRINCE, from the beginning? The reason for my asking is my understanding that Spain has always honored a person's maternal (as well as paternal) heritage (look at the custom of a child inheriting both his father's and mother's surnames). He was, after all, a grandson of Queen Isabel II (in addition to being a nephew of King Alfonso XII, first cousin and later brother-in-law of King Alfonso XIII).
Of course, being a Spanish prince is not (technically speaking) the same thing as being an Infante of Spain: that didn't happen until 1914, when he was formally created into one. By then, he had moved to and settled permanently in the homeland of his wife (Infanta Maria Teresa): I believe he became naturalized as a citizen, after a period of residency. If nothing else, he renounced his Bavarian royal title and succession rights to the kingdom (not that he ever had much of a chance of inheriting it, anyway).
Given that he was an *equally* born prince of royal blood, and husband of a wife with succession rights, his status would have been comparable to that of Archduke Lorenz of Austria (who was declared a prince of Belgium in 1995, four years after his wife and children were inserted into the Belgian royal succession).
That being said, I'm still wondering if -- given the technical difference -- he was (from the beginning) regarded as a Spanish prince, and member of the royal house of Bourbon in Spain. I suppose the question would apply to his younger siblings (Prince Adalbert and Princess Pilar of Bavaria) as well, despite the fact that neither relocated to their mother's home country.