|Kaka, right, aggravated his injury in 'El Clasico' last weekend [GALLO/GETTY]
Brazilian playmaker Kaka could miss Real Madrid's clash with Almeria this weekend as he struggles to overcome a nagging groin injury.
Kaka picked up the strain while on international duty, and aggravated it during the Spanish "clasico" against Barcelona last weekend.
The news is frustrating for coach Manuel Pellegrini who has only just welcomed back Cristiano Ronaldo to La Liga after a two month absence with a twisted ankle.
Kaka is also a serious doubt for the last round of the Champions League group stage against Marseille next week, where Madrid only need to avoid defeat to progress to the next stage.
Kaka has been training apart from the rest of the Real Madrid squad.
"He has been playing through the pain. He has had a groin problem and this perhaps explains his inconsistent performances," Real sports director Miguel Pardeza told Spain's Radio Marca.
"In my day it nearly always required an operation but now there are other types of treatments which are much better, and I am sure he will be back with us again very soon."
Despite losing the "clasico,'' at Camp Nou. Madrid managed to pressure Barcelona for much of the game after a run of mainly unimpressive performances, and their performance did much to boost morale.
"In the Camp Nou we showed that we are at Barcelona's level,'' Madrid defender Pepe said.
"We are clear on what line to follow. We returned from Barcelona without the three points but with plenty of confidence, knowing which is the way forward.''
Barca are now five points clear at the top, having extended their lead with a midweek defeat of Xerez, but coach Pep Guardiola is also having to juggle his squad carefully, with the added complication of the upcoming Club World Cup which starts in Abu Dhabi next week.
The champions face a tough trip to play fifth-placed Deportivo Coruna on Saturday after another shaky performance away from home against bottom club Xerez.
Substitute Zlatan Ibrahimovic's superb last-minute strike made the scoreline more respectable at 2-0 and ended a run of three consecutive away draws.
Guardiola admitted it had been a far from vintage performance although understandable so soon after the "clasico."
"This was a very dangerous game for us right until the end," he said.
"We became bogged down, we didn't move the ball about cleanly, and we were too slow. It's clear we weren't at our best."
Third-placed Sevilla are at home to Real Valladolid on Saturday while fourth-placed Valencia will need to be at their best to take all three points from Athletic Bilbao at San Mames on Sunday.
Atletico Madrid dragged themselves out of the relegation places with only their second win of the season last weekend, and have a good chance to climb further away from trouble at basement side Xerez on Saturday.