He began his professional career playing for LD Alajuelense, in Costa Rica's top division, with only being 18 yearsold. He soon became a great trio with 2 of the best strikers the team has had in last couple of decades, Rolando Fonseca and Froylan Ledezma. There, he won the 2004 CONCACAF Champions' Cup, and the2004-2005 National Championship. He quickly built a reputation as a great goalscorer. He is also a great play maker, and was one of Alajuelense's best players in his last season with them. His brother,Yendrick is also a professional player. He is currently playing for LD Alajuelense. In that club, Bryan was nicknamed "la comadreja" (the weasel), due to his ability and his velocity when he controls theball.
In the summer of 2006, he was signed by K.A.A. Gent in 4-year deal alongside with Randall Azofeifa from Deportivo Saprissa.
He scored his first hat-trick playing for the Gent onDecember 8th 2007 against Lokeren. He was considered as the best player for his team in the last season in the Belgium League, delivering great performances during the games and being the top scorerfor the team. He had been linked with teams such as SC Heerenveen, Anderlecht, Standard Liège, Club Brugge, Olympiacos, Napoli, Newcastle United, and most recently Celtic and Wigan. On May 14, it wasinformed that the Eredivisie champions AZ were interested in the Costa Rican player.
On July 15, 2009, Dutch club FC Twente announced that they had signed the Costa Rican forward forthe sum of €5m. Ruiz signed a 4 year deal with the Eredivisie side. Ruiz made his debut in the 0-2 away win against Sparta Rotterdam. He got off to a perfect start for his new club, by scoring the...