The Los Angeles Dodgers do not know the next time Shohei Ohtani will take the mound due to irritation in his left knee.

Ohtani was slated to start Wednesday against the Philadelphia Phillies, but Dodgers manager Dave Roberts told reporters before Sunday's doubleheader against the New York Yankees that he can't project when Ohtani will throw again.

"Kind of where we're at right now ... I would say that it's going to be some time," Roberts said. "I say that it's not going to be a day-by-day thing."

Ohtani, who made his last mound appearance on July 3 against San Diego, has seen his pitching numbers change dramatically in the last month. He allowed just five earned runs and 30 hits in his first 10 starts (0.74 ERA), but surrendered 12 earned runs and 25 hits over his last four starts (4.38 ERA).

Despite his knee woes, which required a lubricant on July 12, he has been in the Dodgers' lineup each of the last nine games - including Sunday's opener against the Yankees.

In the Dodgers' previous eight games, Ohtani posted a .300/.364/.733 slash line with four homers and eight RBIs. He did, however, sit out the All-Star Game on Tuesday.