The injury comes at the worst possible time for Pepi, who went through a similar situation last January.
"It didn't look good right away, and at such a moment you would prefer to look the other way," PSV head coach Peter Bosz told reporters.
Pepi suffered a season-ending knee injury last January during a strong goalscoring run, an issue that did not fully heal until the fall. Since returning, he had worked his way back into form, bringing his season total to 11 goals with Saturday’s strike - eight of them in the Eredivisie in just 716 minutes - before being sidelined once again.
"Last January Ricardo was already out due to his knee injury," Bosz said. "It won't last that long now, but unfortunately we lost him again. Pepi was on a good run, had a strong training camp and was all the way back. He became more confident and was in that good flow again.
"All signs were green for a strong second half of the season, so this is incredibly disappointing. First and foremost for him and obviously for us as well."
Last season, Pepi's run of form drew interest from Premier League sides, and this season's run was doing the same. Reports indicated that Fulham had made a large offer for the striker, but PSV sporting director Earnie Stewart remained adamant that Pepi wasn't for sale. Now, though, everyone will be solely focused on Pepi's recovery, which should come well before the USMNT decides on a World Cup roster.
