Alvarez was drafted first overall by
Shell Turbo Chargers in the 2004 PBA Draft, ahead of former college rival
James Yap. He played his first PBA game on the team's second game after former coach John Moran benched him in the first game. He thought that Alvarez was not yet ready to play, but when
Leo Austria took over the team's coaching duties, his game status went up and won the Rookie of the Year honors at season's end. In his rookie season, he averaged 8.8 points and 6.4 rebounds in 72 games. As the Shell franchise was about to take a leave of absence from the league, he was traded to the
Alaska Aces along with
Tony dela Cruz, where he struggled in his only appearance with the team during the
2005-06 PBA Fiesta Conference. Prior to the start of the
2006 PBA Philippine Cup, he was traded to the
Red Bull Barako in exchange for two 1st round picks, reuniting him with some of his former teammates in college. In 2008, he was traded again, this time to Purefoods in exchange for Barako's 2011 first-round pick. The following year, he was involved into a blockbuster multi-player deal that sent him to the Ginebra Kings. In 2010, he was traded again, along with
Doug Kramer, to
Air21 in exchange for
Yancy de Ocampo. As his contract with Air21 expired, he signed with
Talk 'N Text prior to start of the
2010–11 PBA season. Initially, he was only signed to a one-conference contract. His competitiveness and renewed fervor rewarded him of a spot at
Kia Sorento for the upcoming
2014–15 PBA season. ==PBA career statistics==