|Full name||Boris Alexis Rieloff Venegas|
|Date of birth||8 January 1984|
|Place of birth||Santiago, Chile|
|Height||1.86 m (6 ft 1 in)|
|Playing position||Right back|
|Current club||Audax Italiano|
|2011||Gimnasia La Plata||10||(0)|
|2012||Deportes Iquique (loan)||36||(6)|
|2013-||Audax Italiano (loan)||6||(1)|
|* Senior club appearances and goals counted for the domestic league only and correct as of 15:42, 10 June 2011 (UTC).
† Appearances (Goals).
After signing as a teenager for Audax Italiano, Rieloff began playing with the youth team. He later graduated to the first adult team in 2004, making his debut on 7 February against Universidad Católica in a 3–2 loss. In the same season and also in the next, he had total of 5 goals in 56 appearances at the age of 21. Because his good performances, Rieloff was nominated to his national team by the coach Nelson Acosta in 2006.
The 2007 season, was one of most successful years in Rieloff's career and including also for Audax history, making historic actuations like achieve 91 points in an accumulate table for first time in Chilean tournaments and in the team history. The next seasons was irregulars for Audax, but goods for Rieloff.
Rieloff's another good season was undoubtedly in 2010, being voted the best right of Chilean football, obviously also being nominated in the Ideal team of the tournament, the player also received an award for defending the italic club for four seasons, during his last game against Unión Española in the 2011 Copa Libertadores playoffs.
Gimnasia La Plata
He made his league debut on 12 February against San Lorenzo as starter, playing the full 90 minutes in a 1–1 draw. Under the coach Ángel Cappa, Boris had good job with the wolf, adapting well to the gameplay until that Cappa was fired and he also had a muscular injury that forced to the player leave the fields for three weeks. However, after the player was fully recovered, the club's new coach Hernán Ortíz not considered to Rieloff in the starting lineup, and was relegated to the reserves team.
On 2 June 2011, was reported that Colo-Colo attempted to sign to the player for second time, after a frustrated negotiation in December of last year. Some days later, Rieloff recognized contacts with the club and he and the institution had reached an agreement for him to play in the 2011 Clausura tournament, once the Argentine tournament finished.
After of joined to Colo-Colo, the player was loaned to Deportes Iquique in 2012.