Real Madrid coach Jose Mourinho will have to make changes to his side\'s attack when they make the short trip to play Rayo Vallecano in the Vallecas stadium on Sunday afternoon. Madrid are without in form Karim Benzema, who pulled a muscle in his groin during Tuesday\'s 1-1 draw away to CSKA Moscow in the Champions League. Benzema will be replaced by Gonzalo Higuain, who is the third highest scorer in the BBVA Primera Liga. The Argentinean has netted 14 league goals this season, a total only bettered by Cristiano Ronaldo and Leo Messi, who have 28 and 27 respectively. Ronaldo will be looking to add to his total as he leads the Madrid attack alongside Higuain. The third place in Madrid\'s attack is also up for grabs after Angel De Maria suffered a relapse of his hamstring injury last Saturday against Racing Santander. De Maria will se sidelined for around a month, meaning that Javier Callejon and Kaka both have options of starting on Sunday. The return of Alvaro Arbeloa from suspension in defense means that Sergio Ramos will move back across to central defense with Arbeloa playing at right back, while either Marcelo or Fabio Coentrao will play on the left. In midfield Mourinho will probably opt to use Sami Khedira alongside Xabi Alonso, in what could be a physical encounter. Khedira\'s greater defensive presence will be important on the short Vallecas pitch where Rayo waste little time in getting the ball in and around their rival\'s penalty area. Meanwhile Mesut Ozil will provide creativity in the final third of the pitch. Although Rayo have one of the smallest budgets in the Primera Liga they are enjoying a fine return to the Primera Liga and after a run of three consecutive wins they have even got a chance of qualifying for Europe at the end of the season. Striker Michu is scoring goals regularly, while loan signing Diego Costa has also been a threat since arriving from Atletico Madrid. Real Madrid are favorites, but this could be one of their toughest away games between now and the end of the season.