He was most comfortable as a winger on either side of midfield, though he could also play centrally in a 4–5–1 formation, or even as a second striker. Ljungberg became a regular in Arsenal's starting line-up following the departure of Emmanuel Petit and Marc Overmars in the summer of 2000. For several seasons he played a major role for the club including being a member of the unbeaten 49-game run for Arsenal. He had to fight with constant injury problems and occasionally severe bouts with migraines; in 2005 a persistent hip injury led to fears he may have contracted cancer, which were unfounded. It transpired that he was suffering from blood poisoning caused by his large tattoos.