Santos certainly earned that nod with the way he had pitched during Spring Training, not to mention the raw talent coming from his arm in the form of a 98-mph fastball. But the converted infielder still wasn't convinced how Tuesday would play out, when the White Sox announced their final cuts. Not with one year of pitching experience under his belt.
"I was even nervous walking into that room," said Santos, who was told the special news of his big league trip to Chicago on Tuesday morning by Guillen, general manager Ken Williams and pitching coach Don Cooper.
"In this sport, you never know what can happen," Santos said. "The second he said, 'to go to Chicago,' it really hit me. And it was like, 'OK, we are finally doing it.'"
And with that news delivered, as Santos walked through the White Sox clubhouse, it was hard for the 26-year-old right-hander to contain his smile.
Just one year ago, Santos was a Minor League infielder with the Giants, having been acquired from the White Sox in an end of Spring Training deal. The 2009 non-roster invite to White Sox camp returned to the Chicago organization through a trade back on April 1, at which point Minor League Director Buddy Bell recommended Santos' move to the mound.
This incredible journey took Santos through stops with Class A Kannapolis, Class A Winston-Salem, Double-A Birmingham, Triple-A Charlotte and into the Arizona Fall League, when the effectiveness of Santos' secondary pitches started to catch up to his high-octane fastball. Suddenly, Santos was drawing notice as a viable addition to the Major League ranks, especially with Santos being out of Minor League options.
Six weeks after his arrival in Arizona, Santos has become one of the top Spring Training stories throughout Baseball.
"Last year, right around this time, we were just carrying this guy because he couldn't play infield," said Guillen of Santos. "I talked to him and said, 'Santos, you don't have one year of pitching. You've only had a few months pitching. I think the reason we keep you is because we know you can help us win games.'"
Guillen also made clear to Santos that this is not a development situation for him, although he will learn on the job. It's a point Santos certainly understands clearly.
"Absolutely. I'm looking forward to that opportunity of going out there and doing my job," Santos said. "Like Coop told me earlier, it's not the instructional league when I'm out there. It's the American League. They are trying to win every game. I'm just doing my little part to help the team win."
"Our job is to try to win this division, try to win everything," Guillen said. "Don't feel like we kept you because we didn't have any choice. I think you earned it. He pitched very, very well and that's the reason he's here."
Veteran reliever Greg Aquino, who was not scored upon this spring over 10 1/3 innings, and left-hander Erick Threets lost out to Santos in the final roster shuffle. In a strange twist, Guillen admitted rookie Daniel Hudson "made the team" but "we just didn't have a space for him."
Hudson begins the season at Triple-A Charlotte, where he will be the ace of the Knights staff and the sixth starter in waiting for the White Sox. He excelled in relief this spring, posting a 1.13 ERA in four appearances, but gave up eight runs in eight innings over three starts.
"That was weird," said Hudson of that discrepancy. "I haven't relieved much, so I don't know why it was. It definitely gives me confidence to know I can [pitch in relief] if they need me to do it."
Jayson Nix earned the last position-player job, beating out outfielder Alejandro De Aza, infielder Brent Lillibridge and the possibility of taking 13 players. Nix was out of options, as well, but provides the White Sox with good power off the bench and versatility in the field.
De Aza, Lillibridge and Hudson were optioned to Charlotte, while Aquino, left-handed pitchers Charlie Leesman and Threets and catcher Donny Lucy were reassigned to Minor League camp. These moves give the White Sox 12 pitchers, two catchers, seven infielders and four outfielders as they get ready to break camp with their 25-man roster.
Once the White Sox reach Chicago, Santos simply is another individual being counted on in relief. For Tuesday, though, an emotional Santos can revel in this remarkable accomplishment of becoming a big league pitcher.
"From my mom and wife, a lot of crying," said Santos of his family's reaction to the news, coming along with 40 or 50 congratulatory texts from friends. "From my dad and my two brothers, just a lot of joy and a lot of pride. It's a day I'll never forget.
"I'm thanking my lucky stars every day. I had my mom praying just in case for backup. It's nice that when you work so hard for something to kind of be rewarded at the end of the day."
Scott Merkin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.