They were led by fellow pitcher Josh Collmenter, who had found himself on the other end of the joke last spring.
Collmenter served as the guide this year and narrated a video of the day shot by someone in the D-backs organization. Eventually the entire team will sit down to watch the video once it's edited.
"I turned the whole thing into a quest for them to become a knight," Collmenter said. "We had contests and games. Whoever won the contest had to wear a little tiara into the next one. Whoever collected the most tiaras ended up winning and ultimately getting knighted by the king at the end of the ceremony."
The contests included climbing a rope swing, playing "King of the Log" and a jousting competition.
"There was some body paint involved, some dart throwing and possibly some pickle eating," Collmenter said.
The rookies were all given new monikers for the day.
Bauer became Trevorium, Skaggs was Sir Longshanks and Corbin was Edward the Bruce. Brewer got to keep his name of Charles because Collmenter felt like it sounded medieval enough on its own.
"I watched 'Braveheart' not too long ago, so I took a couple of names from that," Collmenter said.
Corbin -- er, Sir Longshanks -- won the most contests and was knighted by the King of the Realm.
"I almost had my knighthood," Brewer said. "But I fell just short after the final joust challenge. The important thing is we got out there and had some fun, experienced some new things and got to play with some pretty dangerous weapons, which is pretty cool. Got to meet some really interesting people."
The idea, as with most of the practical jokes in the Arizona clubhouse, was hatched by veteran closer J.J. Putz.
"It's like a double-edged sword," Putz said. "Kind of bring them down to earth a little bit and also make them feel welcomed. The old saying is people don't pick on you and joke around with you if they don't like you. So just trying to make them feel like they're part of the big picture here, because obviously those four kids have great arms and there's a great chance that one if not all of them could help us out during the season."
Bauer was the No. 3 overall pick in the 2011 First-Year Player Draft, while Skaggs and Corbin were acquired from the Angels in the Dan Haren trade in July 2010. Brewer was 5-1 with a 2.58 ERA in 11 starts for Double-A Mobile last year.
D-backs manager Kirk Gibson wanted to make sure that everyone involved understood that there was nothing mean-spirited about the outing.
"That's not hazing," he said. "That's a bad word. Since they were young and so talented and have had so many good things [said] about them, we thought we would give them a little gift and let them have a new experience. That was the intent. It's something they've probably never been exposed to. There's just all different types of people; people do different things, and we do baseball. I think that's equally as important. We use it as a life lesson."
The players seemed to take it in good fun.
"It was interesting," Skaggs said. "It wasn't something I expected, but it was fun. I'd say it makes all of us feel part of the team. It makes all of us rookies get a little closer and kind of shows some of our teammates that don't know us very well another side of us. It was fun. It was a little embarrassing, but it was fun."
Collmenter was asked to serve as guide this year after he impressed the veterans last year with his commentary on the video.
Sunday, though, Putz in his own unique way explained why Collmenter was selected.
"I feel like Josh might be a vampire that was killed in the medieval times and just hasn't aged," Putz said. "He feels very comfortable and at home in medieval times, especially since he provided all the costumes from his personal wardrobe. I think he's a natural."