Aguero was 19 when he played for Atletico Madrid against Bolton in a UEFA Cup tie in February 2008, coming off the bench in the second half but lasting just 12 minutes before he was sent off for spitting at Bolton's Matt Taylor.
He could not have imagined then that his next appearance there would be for City, currently sitting joint top of the Premier League alongside Bolton - albeit after one match - after both produced 4-0 wins in their season-opening games.
The Gunners, who also have Gervinho and Alex Song suspended following last weekend's bad-tempered draw at Newcastle United, are at home, with both sides on one point after the Merseysiders' draw with Sunderland last Saturday.
Chelsea will be without goalkeeper Petr Cech for three or four weeks after the keeper suffered a knee ligament injury but will be looking for their first win after last week's 0-0 draw at Stoke City. They play West Brom at Stamford Bridge.
The 23-year-old Argentine striker recalled: "I spat in the direction of the player but not at the player himself.
"However, the officials thought I had, and they suspended me. I don't know what it will be like when I go back, but hopefully I can make City's supporters happy," he told the Manchester Evening News.
He certainly made them happy on Monday when he came off the bench at around the same time as he had against Bolton, but this time scored two goals on his first appearance since becoming City's record 38.0 million pounds signing.
