• "Grey's Anatomy" Season 13 is slated to make its return on ABC this fall on Sept. 22.

"Grey's Anatomy" Season 13 is slated to make its return on ABC this fall on Sept. 22. (Photo : Getty Images/Angela Weiss)

"Grey's Anatomy" season 13 may see the return of Sandra Oh's Cristina Yang in a cameo.

According to Inquisitr, one fan recently posted a photo of Callie (Sara Ramirez) with two different looks on her face via Twitter. One image showed Callie with a huge smile on her face and the second photo featured the character looking sad. "Grey's with Cristina Yang vs Grey's without Cristina Yang," the caption read.

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The photo went viral and it once again heightened speculations that Oh could reprise her role in the hit ABC series.

Meanwhile, Kelly McCreary spoke with TV Guide last month to say that "Grey's Anatomy" season 13 will focus mostly on the old characters in the series. "After such a long period of time and so many people coming in and out, they remain the foundational characters of the show. We're gonna be spending some more time with them to check in with where they are. The way that we spent time with Meredith last season, exploring the major shift in her life, the loss of Derek, I think we can expect to see those doctors being explored where they are in this moment, all these years later, the changes that they've gone through," she said.

McCreary's words were assumed to have some relation to Oh and the original characters of the series, namely, Ellen Pompeo's Meredith Grey, Chandra Wilson's Dr. Bailey, James Pickens Jr.'s Dr. Webber and Justin Chambers' Alex Karev.

The publication is also speculating on the possible return of Katherine Heigl as Izzie Stevens. However, "Grey's Anatomy" executive producer Shonda Rhimes previously said that Heigl won't return to series after their issue several seasons ago.

In other news, "Grey's Anatomy" season 13 will also tackle some unresolved issues from season 12. This includes Meredith and Nathan's (Martin Henderson) hook up, April (Sarah Drew) and Jackson's (Jesse Williams) possible reunion amid the birth of their baby, and Jo (Camilla Luddington) and Alex's relationship issues.

"Grey's Anatomy" season 13 will premiere on ABC on Sept. 22 at 8 p.m. ET.