The sides will both be looking to return to winning ways having had to settle for a share of the spoils in their most recent involvements.
Match preview
San Lorenzo were denied back to back wins following a 1-1 stalemate in Sunday's clash against Banfield at the Estadio Florencio Sola.
Ruben Insua's men opened the scoring midway through the first half thanks to Adam Bareiro before Matias Gonzalez restored parity in the 38th minute.
As a result, El Azulgrana have now dropped down to 12th place in the league table albeit still five points behind current leaders Godoy Cruz.
Awaiting them next is the challenge of an opposing side who have only emerged victorious in one of the last nine meetings between the teams
Off the back of ending an 11-game winless streak on home turf in their last outing, Wednesday's hosts set out to record consecutive wins in front of their fans for the first time since last December.
Union stretched their unbeaten streak in the league to four games courtesy of a goalless draw against Huracan at the Estadio 15 de Abril on Sunday.
Despite playing the final 20 minutes of the game with only 10 men, Gustavo Munua's side held firm to secure a hard-fought point in Santa Fe.
El Tate have slipped to ninth place in the standings but they remain just two points off top spot in what is set to be frenetic battle for supremacy this year.
Having scored the joint-most goals on enemy territory in the entire division so far, Wednesday's visitors will head into the encounter with the wind in their sails.
San Lorenzo Argentine Primera Division form:
Union Argentine Primera Division form:
Union form (all competitions):
Team News
Uruguayan forward Jonatan Alvez is unavailable for Union de Santa Fe having missed each of the last three matches through a foot injury.
Matias Gallegos will not also play any part due to a slight knock which he picked up in his second-half cameo against Banfield on Wednesday.
Twenty-four-year-old Franco Calderon is suspended for this one after receiving his marching orders in the visitors' most recent outing.
Nicolas Blandi and Jeremias James are ruled out for San Lorenzo through injury, while Yeison Gordillo is also sidelined at the moment.
Off the back of a five-game scoring streak, Adam Bareiro currently leads the scoring charts with six goals and he is one to look out for here.
San Lorenzo possible starting lineup:
Torrico; Campi, Zapata, Hernandez; Giay, Mendez, Rosane, Fernandez; Cerutti, Bareiro, Barrios
Union possible starting lineup:
Mele; Corvalan, Polenta, Gerometta, Vera; Portillo, Machuca, Roldan; Luna Diale, Troyansky, Castrillon