- Bats Right, Throws Right
Ronald Jaarsma made his Hoofdklasse debut in 1999 with HCAW. In 2000, he tied for 8th in the league in steals (11). In the 2001 World Port Tournament, he was 2 for 11 with 2 walks. In the 2001 European Championship, he was 3 for 8 with two walks and four runs. In 2002, he ranked among the leaders in runs (31, tied for 7th with Evert-Jan 't Hoen, hits (53, 7th) and steals (15, tied for third). Jaarsma was not among the leaders in 2003. In 2004, he tied for 6th with 45 hits, matching Johnny Balentina, Michael Duursma and Dè Flanegin. Jaarsma hit .213/.324/.352 in 2005 but still tied Duursma and Denny Beljaards for sixth in the league with 9 steals. In 2006, he batted .293/.402/.348 but was caught stealing in 6 of 10 attempts. He slipped to .227/.314/.241 in 2007 and stole 16, but was caught 8 times. He tied Raily Legito and Johnny Balentina for the lead in steals.
Jaarsma retired after the 2008 season to serve as an assistant coach for HCAW. He coached for the Netherlands in the 2010 Women's Baseball World Cup.