Arroyo played in the BSN for the Cangrejeros de Santurce, where he was a teammate of the first Puerto Rican to play in the NBA, Jose Ortiz. He and Ortiz helped the Cangrejeros to four consecutive titles in the late 1990s, and to five titles in six years. Arroyo announced he will not participate in the 2004 BSN season.
Arroyo was hired in the NBA by the Toronto Raptors for the 2001-2002 NBA season, but he was promptly traded to the Denver Nuggets. He saw limited action with those two teams, playing seventeen games with the Raptors and twenty with the Nuggets before his inicial NBA season was over. He only played an average of 9.7 minutes per game during those thirty seven games where he saw action.
With the impending retirement of John Stockton, the Jazz needed a reliable, replacement point guard on their team. They envisioned Arroyo as being the player who could substitute Stockton, and they traded for him before the start of the 2002-2003 NBA season. Arroyo was then relegated once again to watching games from the bench most of the season, but head coach Jerry Sloan and his team of assistants instructed Arroyo to observe Stockton and back-up guard Mark Jackson, who was also nearing retirement.
Arroyo was given the starting job at his position after Stockton and Jackson retired before the start of the 2003-2004 season. He has surprised many Utah Jazz fans, qualifying among the top twenty players in the NBA for the season in various categories: As of November 2003, he was ranked eleventh in assists per game, and in assists per 48 minutes played. He also ranked sixteenth in two other categories. On November 14, he broke the record for the most points scored by a Puerto Rican in an NBA game, scoring 30 points against the Minnesota Timberwolves.
Arroyo also played in Spain, in 2001.
As of November 2003, he has 397 points, for 4.4 points per game, 187 assists for 2.1 assists per game, and 93 rebounds, for 1.00 rebounds per game.
His per game numbers are widely expected to arise as his career progresses, because he has been given much more playing time each game as a result of Stockton and Jackson's retirements.