The latest edition of The Wrestling Observer says that Rusev could potentially feud with John Cena at some point down the line. While that feud is not confirmed, it's not surprising that WWE would be looking for a major star for Rusev to work in the near future.
We reported that WWE was modeling Rusev's push after the late Umaga, who worked mostly squash matches after his debut. Umaga got big wins over the likes of John Cena, Triple H and Shawn Michaels before he aligned himself with Vince and Shane McMahon. If memory serves correctly, Kane was Umaga's first "real" feud that lasted any significant amount of time.
It's unknown how long WWE will continue with Rusev before they put him in a significant angle or feud of some kind, but a program with Cena has at least been discussed.
Alberto Del Rio PSA Video
WWE has released a new PSA video featuring Alberto Del Rio with his son. You can check it out below: