Cena wrestled Rusev at today's WWE live event in Shenzhen, China and defeated him in a match that took place before intermission. Cena would be able to fly out of China and make the 17 hour flight to San Jose for RAW.
It's worth noting that Cena is still not being advertised by the WWE website or by the SAP Center website.
WWE's official preview for Monday's RAW has the following blurb for Cena and Reigns, which sounds like they are planning on Cena's absence:
Will it be Roman Reigns or John Cena who gets in the final word before WWE No Mercy?
John Cena and Roman Reigns' microphone battles have gotten more intense each week since The Cenation Leader arrived on Raw to test Roman Reigns' mettle, and a heated confrontation six nights before their anticipated dream match at WWE No Mercy seems inevitable.
Although Cena seems to have the upper hand in terms of verbal warfare heading into this week's Raw, live in San Jose, The Big Dog could be saving his most cutting remarks for last.