A cluster of high-profile players - including Diego Costa and Thiago Alcantara - have suffered worrying injuries in recent weeks that put their participation at the FIFA World Cup in jeopardy, while Victor Valdes will definitely miss out after undergoing knee surgery this week.
Radamel Falcao continues his rehabilitation from a knee injury and Cristiano Ronaldo was substituted during Real Madrid's 3-0 win over Borussia Dortmund in the UEFA Champions League in midweek with a minor knee problem.
Alonso believes the hectic fixture schedule that players have to contend with leaves their bodies at risk of injury and wants to see changes to allow more recovery time.
"He (Ronaldo) has a minor problem, like many other players," Alonso said at a promotional event. "But it is true that the schedule is very tight.
"Since September we've been playing Wednesday-Sunday and finally the World Cup is approaching.
"Diego Costa has been injured, Marcelo has been injured, and there will be more injuries.
"We have to get a more sensible calendar.
"We started playing in the cup (Copa del Rey) in January and we don't have the rhythm other countries have."
Alonso, who suffered a knee injury at the start of the season, has made 36 appearances at club level this term and Real potentially face another 12 games in 2013-14 should they reach the Champions League final.
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