Fernandez-Castano's top-20 finish at the Masters included a third round in the company of Tiger Woods, following on from the world number one's dropped-ball controversy.
Next stop for the genial Spaniard, nicknamed 'Gonzo', is the venue for the only European Tour event this season in his home country.
"It's an indescribable course, there aren't many left like it, a work of art that must be kept and cared for as if it were a Goya or a Picasso," the 32-year-old told the European Tour website.
"Hopefully, we will get some wind, which is its main defence, to add to the spectacle," added the world number 31.
Fernandez-Castano said he was sad that the financial crisis, which has crippled his country's economy, has also deprived Spain of more top-level tournaments.
"It's a shame that we have only one event in Spain this year, and that's the reason why I am here," said the six-times European Tour winner.
"Had it been a different tournament, I would have taken a break, but it's my national Open. I know that Reale and the other sponsors, together with the Federation, have made a great effort to maintain it, so I'm happy to support it."
Fernandez-Castano has been grouped with compatriot Miguel Angel Jimenez, who is making his return to action after breaking his leg skiing, and Italian teenager Matteo Manassero in the first two rounds.
Jimenez, the oldest winner in European Tour history, said he was not yet 100 per cent fit but wanted to test himself on the El Saler course near Valencia where he tied for third in 2001.
"My leg is improving daily. I work out every morning in the gym and I'm actually a little ahead of schedule on my rehab. I can't wait to be back on Tour with my friends," said the 49-year-old who is making his 599th tour appearance.
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