Barcelona tracking Borussia Dortmund defender Mats Hummels?

Barcelona have been linked with a summer move for Borussia Dortmund centre-back Mats Hummels.

Blaugrana are believed to be keen on strengthening their defensive options having been left short this season due to a number of injuries to Carles Puyol.

The German international has been instrumental in Die Borussen's back-to-back Bundesliga triumphs, and that has reportedly attracted the attention of Barca.

According to Football Espana, the 24-year-old has been been scouted over a number of games this season, but he could cost as much as €30m (£28.8m).