"That was my intention my whole time, to graduate," Castro said via cell phone while vacationing in Hawaii. "I was so close when I was [drafted]. It wasn't a question of getting it. It was question of when."
Castro was selected in the 2008 First-Year Player Draft after his junior year at Stanford, 25 units shy of a degree. He got 15 out of the way in 2010, leaving just 10 -- equaling two classes -- to take care of this offseason. While he always knew he'd get his degree, he had to wait until the timing was right. A knee injury a couple of years ago necessitated a concentration on rehab during the offseason, which pushed back his plans to return to school.
Fully healthy and comfortable in his role as the Astros' full-time catcher, and one year after marrying his wife, Maris, whom he met at Stanford, Castro saw the current offseason as an opportune time to sneak away and finish up the coursework.
"It was a matter of when did I have an offseason where I wasn't rehabbing," he said. "I would have done it sooner, but 2011 I had to go to fall league and rehab. This was really the first time to get back and finish what I had left."
Having so few credit hours remaining wasn't a coincidence. It was by design, a byproduct of his coach and advisers making sure Castro was in a good position to have very little left to do in the event that he left school early.
As freshmen, Stanford baseball players are advised to go as heavy on the coursework within their first three years, so in the event that they are drafted, they're still in good position to obtain their degrees.
Head coach Mark Marquess is a big proponent of getting ahead right away, which has helped scores of ballplayers eventually graduate.
"It helps the player get the degree, and it helps the program and the graduation rate," Castro said. "A lot of Stanford guys have graduated regardless of their playing careers. Most guys after their junior year have just a quarter left. They stress getting ahead of the curve so you don't have a full year or more after you leave to try to make up."
Castro isn't the first Astros player to go this route at Stanford. Former infielder/outfielder Eric Bruntlett was a four-year player before he was drafted, but he finished his coursework in 3 1/2 years, leaving getting to the field on time as his only real responsibility spring quarter of his senior year.
"A lot of guys that stay for their senior year actually don't have class spring quarter," Castro said. "They get internships or jobs and come to field for practice."
Although it felt pretty strange to be back on a college campus after several years away from the scene, Castro was able to blend in anonymously. No one in his classes recognized him or knew what he did for a living, or that he was several years removed from being a full-time undergraduate at the prestigious university.
"A couple classes had decent amount of freshmen, which was funny," Castro said. "All the kids looked a lot younger than I felt when I was there. It was pretty startling."
Castro finished his three-year Stanford career with a .309 batting average and ranked in the school's single-season top 10 for at-bats and hits. He posted a .992 fielding percentage, making just 10 errors in 1,187 total chances. He was selected by the Astros in the first round of the 2008 Draft, 10th overall, and made his Major League debut in 2010. His 2011 season ended in Spring Training, when he blew out his knee on an awkward play at first base. Castro returned in 2012, appearing in 87 games.
The 2013 season marked a return to normalcy. Castro played in 120 games and established himself as the Astros' front-line catcher.
While Castro hopes to have a long and fruitful Major League career, he also has his eye on life after baseball as an active player. In that respect, having a college education is a priority.
"We can't play baseball as long as we'd like," Castro said. "At some point, I'll probably put [the degree] to use. Who knows what, but just having it and knowing it's something done and out of the way, when baseball is over, it's nice."