Their trip itinerary was mostly loose and lean, allowing for the whims of a 20-something crowd -- see this, skip that. That is, with one very notable exception.
"This whole trip was about going to the football game," Alonso said.
Not just any football game, but one involving Alonso's favorite team, Real Madrid, who had a game set for the night of Dec. 17 in Madrid against the Sevilla Futbol Club.
Alonso excitedly pulled on his Real Madrid jersey that night and had VIP passes in hand, something the Cincinnati Reds had arranged for him. He was only minutes from bolting out the door.
"We were just waiting for his sister to get ready," said Orioles infielder Manny Machado, a close friend from Miami who was also on the trip.
Then his phone rang. But who would call him in Spain, he wondered. Alonso glanced down to his phone to see the Cincinnati area code of 513 flashing in front of his eyes. He had heard his name mentioned in trade rumors. But now? His heart sunk.
"Not while I'm overseas," Alonso whispered, knowing what was about to occur.
On the phone was Reds general manager Walt Jocketty, who called to tell him he was a part of a 4-for-1 deal to the Padres. Alonso heard Jocketty say that he would have a better chance with the Padres, something about how this would be a good fit for him. He only digested part of the conversation.
"He was in shock," Machado said.
Finally, after fielding a handful of phone calls, many from people he had never heard of, let alone ever met, Alonso tried to cast aside his shock as he and his crew walked to Estadio Ramon Sanchez Pizjuan to see Real Madrid.
Once there, Alonso's mind drifted. How would it all work out? A new city, new teammates. Alonso was nearly oblivious to what was playing out in front of him, as Real Madrid superstar Cristiano Ronaldo was peppering the home goal for a hat trick.
"I couldn't enjoy myself," Alonso admitted.
Only when he returned stateside was Alonso able to truly embrace this opportunity, the chance to step outside the immense shadow of Joey Votto, a substantial roadblock for the 25-year-old Alonso, a player the Reds liked so much that they tried him in the outfield and even hit ground balls to him at third base to see if there was any possible way he could be a part of their future.
Unable to do so, the Reds, needing a top-of-the-rotation starter to pair with Johnny Cueto, dealt away Alonso and others for Mat Latos. And just as Jocketty had predicted that night on the phone, Alonso fit in well with the Padres.
Today, Alonso finds himself in the conversation for the National League Rookie of the Year Award. He probably won't win it, but the Padres know that they have landed what they coveted most last winter: a durable, doubles machine with a sweet left-handed swing to match an advanced approach at the plate, a rarity for a young player.
Going into Tuesday's game against the Dodgers, Alonso is hitting .275 with 35 doubles, 60 RBIs and nine home runs. Alonso has more hits (142), doubles (35), and walks (59) than any other National League rookie, all while playing half his games in a ballpark that suppresses offense, especially for left-handed hitters, no matter their size, shape or strength.
Alonso has, by all rights, become just the player the Padres hoped he would when they made that deal, when they parted with a talented, controllable pitcher in the 24-year-old Latos. Alonso was a piece to the deal with the Reds all along, even though the Padres actually already had a young first baseman on the roster with plenty of potential in Anthony Rizzo.
"We were hoping for a really consistent player, someone who matched up against all the pitching, left and right," said Padres general manager Josh Byrnes, who eventually dealt Rizzo to the Cubs. "... It's hard for young players in our division to break in, offensively. You've got to earn it in the NL West. He's dealt with highs and lows, and he's giving us good at-bats every day."
That much, of course, can be discerned by reading a box score. Dig deeper and you'll see that he has hit left-handed pitching reasonably well (.262 average) and that he hasn't been tamed by his own ballpark, producing a slash line of .277/.366/.403 at Petco Park that might even make Adrian Gonzalez blush.
This is why Byrnes insisted that Alonso be part of the package from the Reds, a deal that was first discussed at the Winter Meetings in Dallas. After all, the Padres were giving up a lot in Latos, who improved to 13-4 with a victory on Saturday that clinched the NL Central. Latos was a top-of-the-rotation arm and the Padres didn't have many of those.
Really, how many teams do?
"If we're going to trade Latos ... we felt we needed a significant package and the right guys," Byrnes said.
In the end, Byrnes got Alonso, a switch-hitting catcher with power in Yasmani Grandal, who could be the catcher for the next decade, starting pitcher Edinson Volquez, an innings-eater who has won 10 games and is under team control next season and a young reliever in Brad Boxberger.
But Alonso was a critical piece to the trade and a player the Padres had watched closely in 2010 and last season. Former Padres pitcher Kevin Jarvis, a professional scout for the organization, is one of a handful of scouts who evaluated Alonso.
"The thing that sticks out when you watch him play is the bat and the advanced approach he has," Jarvis said. "When you watch him over 20, 25 at-bats you see that he's got the ability to make adjustments to different velocity and recognize spin. He doesn't take many bad swings, and he's able to keep the barrel on the bat."
Still, Alonso's first full big league season has been anything but a blissful walk in the park. He struggled in the field early in the season, though his defense has been better in the second half. He has gone through stretches at the plate where he felt lost. At times, it looks like Alonso couldn't be pitched to.
Take the Padres' wild 12-11 victory over the Rockies at home on Sept. 16. The box score will show you that Alonso had four hits and knocked in the winning run in the bottom of the ninth inning with an RBI single. What it won't show is that how in the third inning, with his team trailing 5-2, he was thrown out trying to go from first base to second on a fly ball to center field.
He was thrown out by five feet and the Padres didn't score again that inning.
"That Sunday was a good depiction of how the season has been," Alonso said. "I had my head down as I was running to second, and I didn't see the throw. I've got to do a better job of knowing the situation. I have to run with my head up. I'm a strong believer in being the best teammate I can be. When I made that blunder, I wasn't being the best teammate."
But those times have been few and far between for Alonso, who has contributed far more than he's hurt his team, his new team. Whereas he once envisioned himself the next great Reds first baseman, he finds solace in knowing that he'll be here in San Diego for a while.
As for that dream vacation, complete with seeing a Real Madrid game, Alonso has found a remedy for that. He has planned another trip this offseason, determined to enjoy himself. He's optimistic that he won't get a life-alerting phone call this time.
Alonso then turns his head and smiles.
"We'll see what happens," he said.