The Brazilian striker, a transfer deadline-day acquisition from Real Zaragoza, returns for a second spell at a club where he was their top scorer with 22 goals in the 2004-5 season.
Betis have slumped to 16th in the league this term and their coach Paco Chaparro has been feeling the heat. However, a derby against near neighbours Sevilla presents a chance to ease the pressure.
"We will improve because we have lacked a striker like him (Oliveira), and he has looked sharp in training," Betis midfielder Arzu said.
"Although he has been the centre of attention, and treated as a saviour, what's most important is that he helps us to win."
Sevilla have not lost to their rivals since April 2006 and are riding high in third place.
However, they have less time to prepare after grabbing an injury-time goal to win 2-1 against Athletic Bilbao in a draining King's Cup semi-final first leg on Wednesday.
Runaway leaders Barcelona continue to set the pace but have needed strong second-half performances to win their last two games against sides with well-organised defenses.
Unfortunately for Sunday's visitors Sporting Gijon, defending has not been their strong point. They have the league's leakiest defence with 44 conceded.
GLIMMER OF HOPE
However, a glimmer of hope for Sporting could lie in the defensive changes forced upon Barca coach Pep Guardiola. Gerard Pique, Rafael Marquez and Daniel Alves are all suspended, while captain Carles Puyol is an injury doubt.
Champions Real Madrid, who are 12 points adrift in second, will be seeking their seventh consecutive victory when Racing Santander travel to the Bernabeu on Saturday. Real's new signing Julien Faubert could get his first run out in the side.
Atletico Madrid's run of seven matches without a win in all competitions saw them slip out of the European places into seventh and coach Javier Aguirre was shown the door earlier this week.
His replacement Abel Resino takes the reins for the tricky trip south to face Recreativo Huelva on Sunday. Improving Recre are unbeaten in five games.
Like Atletico, fifth-placed Villarreal need to reverse a slide that has seen them win once in their last eight league outings.
Manuel Pellegrini's side will be expected to see off lowly Numancia at the Madrigal on Sunday.
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