The Andalusians suffered a summer of financial unrest and had to sell star players Santi Cazorla and Salomon Rondon just to meet some urgent debts.
However after progressing to the group stages of the Champions League for the first time in the club's history, Pellegrini was able to bring in Javier Saviola, Manuel Iturra and Roque Santa Cruz.
He told Marca: "We are trying to form a good group. We now have the opportunity to strengthen that group and only time will tell if it is adequate or not, but with these additions we are left with a more competitive squad.
"Saviola and Santa Cruz have an important trajectory due to their quality and the number of goals they have scored in their career. Both come to offer goals, which was the biggest deficit we had in the squad. On the other hand, Iturra will offer us a lot in the centre of the field. He recovers the ball well and is good technically. The three fit into the reinforcements we were hoping for."
However, the Chilean is unlikely to call on any of the three for this weekend's trip to Zaragoza. Eliseu is suspended and Seba Fernandez has been ruled out with a calf problem so there will be more first-team action for youngsters Fabrice Olinga, Juanmi and Francisco Portillo.
Zaragoza winger Lucas Wilchez could be involved after recovering from an abductor injury that has impeded his participation in the first few weeks of the season and he insists he is ready to play wherever manager Manolo Jimenez instructs him to.
He told the club's website, "I am over my injury and I am ready to play. Full-back isn't my position, but if I have to play there I will because I am so desperate to play."
The reason the Argentine may have to fill in at full-back is that Ivan Obradovic and Glenn Loovens are both still out injured.