Barcelona are already eyeing reinforcements in the summer transfer window. La Liga giants Barcelona are set to raid Eredivisie side Ajax for youngsters Matthijs de Ligt and Frenkie de Jong in the summer transfer window.Barcelona are on course to win La Liga and are have already won the Spanish Copa del Rey, but after a disappointing exit in the Champions League quarter-final by Roma, the club are set to reinforce in the summer.The Catalan club are reportedly ready to strengthen in defence and midfield in the transfer window.According to a report by Spanish media outfit, Mundo Deportivo Barcelona are making plans to sign both Matthijs de Ligt and Frenkie de Jong this summer or the next to inject younger players into the team. The report states that both De Ligt and De Jong are considering if it is the right time to move away from Ajax where they are guaranteed regular football.Barcelona are however willing to make a down payment to secure the services of the duo for the next transfer window in 2019 according to the report.De Ligt is considered by Barcelona as a formidable defender at just 20-year-old while De Jong is just 18-year-old but already a key part of the Ajax midfield. Despite signing Yerry Mina in the winter transfer window from Palmeiras for £10.5million, Barcelona are keen to add De Ligt who is seen as a future replacement for Gerard Pique.While De Ligt is seen as another midfield reinforcement in preparation for the impending departure of Andres Iniesta even though Arthur Melo arrives in the summer.