In 2020, Castro announced he's retiring from racquetball to focus on baseball with the hopes of representing Chile at the 2023 Pan American Games.

[12] In the 2008–09 season, Castro lost to Jamie Slamko, 15–13, 15–6, in the Round of 32 at the 2009 National Team Selection Event in Brossard, Québec.

[15] In January 2010 in Brossard, Québec, Castro defeated Josh Keil in the Round of 32, then lost to Mike Green, 15–8, 15–7.

[16] But at the 2010 Canadian Championships in Burnaby, British Columbia, Castro had a then career best result, as he reached the quarterfinals for the first time.

[19] At the 2011 Canadian Championships in Nova Scotia, Castro matched his quarterfinal performance from the previous year, losing that time to Kris Odegard, 15–0, 15–9.

[24] In November 2012, at the first National Team Selection Event of the 2012–13 season in Kelowna, British Columbia, Castro lost to Nathaniel Husulak, 15–4, 15–9, in the quarterfinals.

[25] But in the second National Team Selection Event in Brossard, Québec in February 2013, Castro had his best singles result, as he reached the semi-finals – beating Husulak in the quarters, 15–6, 15-11 before losing to Tim Landeryou, 15–7, 15–10.

[26] The 2013 Canadian Championships were in Langley, British Columbia, where Castro reached the quarterfinals with a win over Samuel Murray, 15–13, 15–9, in the Round of 16, before losing to Mike Green, 15–9, 15–4.

[28] At the second National Team Selection Event of 2013–14 in Brossard, Québec, Castro was a quarterfinalist, as he lost to Coby Iwaasa, 15–4, 15–5, in the quarters.

[29] Castro represented Canada for the first time at the 2014 Pan American Championships in Santa Cruz de la Sierra, Bolivia, where he played Men's Doubles with Tim Landeryou.

[30] However, in doubles Castro played with Tim Landeryou for the first time, and they reached the finals, where they lost to Vincent Gagnon and Samuel Murray, 15–12, 15–2.

[34] Castro represented Canada in Men's Singles at the 2015 Pan American Championships in Santo Domingo, Dominican Republic.

[38] At the 2nd Selection Event of the season in Grande Prairie, Alberta in early 2016, Castro was again 4th, as he lost in the semi-finals to Green again, 15–0, 15–12, and was beaten by Murray, 15–6, 15–1, in the 3rd place match.

The pair came home with bronze medals after losing in the semi-finals to Mexicans Alejandro Landa and Javier Moreno, 15–11, 14–15, 11–4.

[44] At the National Team Selection Event in November 2016 in Valleyfield, Québec, Castro lost in the quarterfinals to James Landeryou, 15–6, 5–15, 11–3.

[49] In the first National Team Selection Event of the 2017–18 season in November 2017 in Vernon, British Columbia, Castro lost in the quarterfinals to Coby Iwaasa, 18–16, 14–4, forfeit.

At the 2018 Canadian Championships, Castro finished 4th in Men's Singles, as he lost to Samuel Murray, 15–0, 15–13, in the semi-finals, and forfeited the 3rd place match to Tim Landeryou.

[52] In doubles, Castro partnered with Michael Leduc, and they lost to brothers Tim Landeryou and James Landderyou, 15–3, 17–15, in the quarterfinals.

[58][59] Castro didn't compete in either of the National Team Selection Events of the 2019–20 season, and announced his retirement from racquetball in August 2020.

[2] Castro has represented Canada seven times, and made the podium once, earning a bronze medal in Men's Doubles with Tim Landeryou at the 2016 Pan American Racquetball Championships.