He said it comes down to the atmosphere created by the fans. They yell. They bring instruments. They make noise.
"Middle of your pitch, and you just, 'Dum, tee, dum, tee,' you're like, 'Oh, my god,'" Barbosa said, imitating a drum noise.
He said the home crowd booed when he pitched poorly. Fans yell at the manager to pull the pitcher from the game. Barbosa, who moved from Puerto Rico to San Antonio when he was 4 years old, said it was difficult to adjust in his first year in the PRWL.
It's comparable to a soccer atmosphere.
Barbosa's not the only player in the Brewers organization who has experienced the raucous crowds in Puerto Rico. There are six players with Puerto Rican ties either on the Brewers' roster or in camp as non-roster invitees.
Rene Garcia, a 26-year-old catcher, played in Puerto Rico and in the Dominican Republic, which he said has crowds that are just as crazy.
Garcia laughed when asked if the noise makes catching difficult.
"Nah," he said. "Makes it easy."
Garcia and Barbosa haven't been on a team together, but each knows the other's game well. Garcia said he learned the left-handed Barbosa's pitching style while hitting against him in the PRWL and called his changeup "funky" due to the submarine release.
Barbosa credits the catcher with being able to call pitches he's comfortable with in different situations.
"It's just one of those where he puts a sign down, I can throw it," Barbosa said. "I trust him."
Infielder Yadiel Rivera, a 24-year-old from Puerto Rico, occupies a locker just a few feet away from Barbosa at Maryvale Baseball Park.
Rivera has lived in Puerto Rico his whole life and played in the PRWL from 2012-15. He said it helps him to meet players who have more experience than playing in the U.S. Minor Leagues.
A lot of other Puerto Ricans in Minor League baseball go through the Winter League, and the country's baseball team competes in the Caribbean Series every winter. Rivera was on the winning team this Caribbean Series, when Puerto Rico defeated Mexico to win its first title since 2000.
"Pretty much you know everybody in Puerto Rico," he said. "If you play ball in Puerto Rico, you're used to seeing every guy."
Hiram Burgos and Ivan de Jesus are Puerto Rican players on the Brewers' non-roster invitee list. So is Jorge Lopez, whom Rivera met around the age of 16.
Lopez is now pitching for the powerful Puerto Rican team, which has advanced to the second round in the World Baseball Classic. They were September callups last season, and Rivera smiled when reminiscing about getting to the big leagues with his countryman.
"It's awesome to be here with him," he said. "It's funny because we played in Puerto Rico, and now we play in the big leagues together. We made it."