*Club domestic league appearances and goals, correct as of 11 November 2024 ‡ National team caps and goals, correct as of 21:12, 18 November 2024 (UTC)
Contreras joined C.S. Herediano in 2015, after he was spotted by a scout in a game for a club in Zapote, at the age of 15.[3][4] He then went on a trial at the club and then joined the club permanently. Before that, Contreras had never played for a club.
23 months after joining Herediano, on 15 January 2017, he got his official debut for the club in the Liga FPD against Belén FC at the age of 16.[5] Contreras started on the bench, coming on as a substitute for Heyreel Saravia in the 90th minute. This game was his only appearance in the 2017-18 season. In the following season, he only made one appearance, while he made zero in the 2018-19 season. To gain some experience, he was loaned out to La U Universitarios in the summer 2019 for the rest of the year, where he played 20 games as scored six goals.
On 13 December 2019 it was confirmed, that Contreras would be playing the rest of the 2019-20 season on loan for Municipal Grecia, as well as six other players that Grecia had loaned from Herediano.[6][7] Contreras played 15 games and scores six goals for the club.
Herediano announced in June 2020, that Contreras had returned to the club.[8][9] Contreras participated in the teams pre-season and was also on the bench for a cup game in August 2020. However, on 15 September 2020, he was sent out on loan for the third time, this time to Guadalupe FC for the rest of 2020.[10]
Returning from loan in January 2021, Contreras became a regular player for Herediano and made 26 league appearances from January to June 2021. However, on 21 June 2021, Contreras was loaned out to AD Guanacasteca for the rest of 2021.[11]
Riga FC
On 16 July 2023, Contreras joined Latvian Higher League side Riga FC.[12] Contreras made a good start to his time at the club, scoring three goals in his first three league games.
Riga FC announced in January 2024, that Contreras was sent out on loan to Pafos FC.[13] Contreras returned to Riga ahead of the 2024-25 season.[14]