Ramírez made his debut for the Atlanta Bravesin2003, when he finished the season 12–4 with a 4.00 ERA in 29 starts.[1] At the end of his rookie season, he was selected to the Baseball Digest All-Star Rookie team. He got off to an excellent start in 2004, posting a 2–4 with a 2.28 ERA in his first nine starts, before he suffered a shoulder injury and was placed on the disabled list on May 30.[2] While initially thought to be a minor injury, Ramírez was not activated until September 26.[3]
In2005, Ramírez finished with a record of 11–9 and an ERA of 4.63 in 33 games (32 starts), pitching over 200 innings for the first time in his career.[1] He remained in the Braves' rotation in 2006 as the number 3 starter, going 5–5 with a 4.48 ERA in 14 starts.[1]
On December 6, 2006, the Braves traded Ramírez to the Seattle Mariners for right-handed relief pitcher, Rafael Soriano.[4][5] In his lone season with Seattle, he posted a record of 8–7, but had an ERA of 7.16 in 20 starts.[1]
On March 12, 2008, Ramírez was released by the Mariners.[6]
On May 21, 2008, Ramírez signed a minor league deal with the Kansas City Royals.[7] He pitched in 15 games for the Royals out of the bullpen, going 1–1 with a 2.59 ERA.[1]
After his release from Kansas City, on June 15, 2009, Ramírez signed a minor league deal with the Washington Nationals.[11] He became a free agent on November 9.
On February 1, 2010, Ramírez signed a minor league contract with the San Francisco Giants.[12] He became a free agent following the season on November 6.
On March 11, 2011, Ramírez signed a minor league deal with the Los Angeles Angels of Anaheim. On July 20, 2011, the Angels purchased Ramírez's contract.[13] He worked out of the bullpen once again but was not effective, going 1–0 while allowing 16 hits in nine innings and recording a 6.00 ERA in 12 games. He became a free agent after the season.[1]
On August 17, 2012, Ramirez signed with the Chicago Cubs after being released by the Kia Tigers.[16] He elected free agency after the season on November 2.
On July 5, 2013, Ramirez signed with the Tigres de Quintana Roo of the Mexican League.[19] In 6 starts 40 innings he went 3-2 with a 3.38 ERA and 24 strikeouts.
On March 10, 2014, the Braves announced that Ramirez would be joining their coaching staff as a coaching assistant. He was brought on to assist the coaching staff with on-field duties prior to games and manage the Braves instant replay protocol from an off-field location during games.[20]
On March 5, 2016, Ramírez began a professional comeback signed with the Toros de Tijuana of the Mexican Baseball League. Starting 21 games for Tijuana, he logged a 6-4 record and 4.15 ERA with 49 strikeouts in 102.0 innings pitched. In 2017, Ramírez started 11 games, posting a 4-3 record and 4.06 ERA with 25 strikeouts in 62.0 innings of work. He started 12 games, appearing in 16, for Tijuana the following year, recording a 3-2 record and 3.94 ERA with 28 strikeouts in 64.0 innings pitched.
For the 2019 season, Ramírez made 32 appearances for the Toros, pitching to a 4-0 record and 2.60 ERA with 9 strikeouts in 34.2 innings of work. He did not play in a game in 2020 due to the cancellation of the LMB season because of the COVID-19 pandemic.[21] On June 8, 2021, Ramírez re-signed with the Toros.[22] He made 12 appearances (10 starts) for Tijuana in 2021, working to a 3-3 record and 4.50 ERA with 17 strikeouts in 50.0 innings pitched. He did not play in a game for the team in 2022 and was released on January 19, 2023.[23]