The Uruguayan striker suffered the injury in the second half of Wednesday night's 2-0 defeat away to Real Madrid in the second leg of the Spanish Super Cup, although he played on to the end as Barcelona lost 5-1 on aggregate.
"Luis Suarez will be out of action for around four weeks. Tests carried out on Thursday morning confirm that the Uruguayan has a distension in the posterior articular capsule in his right knee picked up in the second half of the Clasico on Wednesday in the Santiago Bernabeu," said Barcelona in a statement in English published on their website.
He will also miss Uruguay's World Cup qualifying ties against Argentina on August 31 and Paraguay on September 5 and is likely to sit out his club's first Champions League group game on September 12 or 13.
Barcelona also revealed that defender Gerard Pique is a doubt for the meeting with Betis due to a groin strain, meaning further bad news for the Spanish giants whose summer has been overshadowed by the sale of Neymar to Paris Saint- Germain.