Pettis is a good dude. Been a fan since he beat Shane Roller back in WEC. I know he's had a tough run lately. While I'd point out that losing to a beast like RDA, a legend like Alvarez, and a top-tier guy like Barboza is no shame, the fact remains that it is problematic to lose three in a row and very dispiriting for a former champ.
Featherweight should be a good place for him. Barboza just looked far physically stronger than Showtime.
Oliveira is definitely a scary first fight in my opinion though. Pettis has, at times, looked hesitant to pull the trigger. Oliveira doesn't have that problem. He's a do or die type- either he's pushing the pace, attacking, doing damage and pressing for the sub or he's getting hurt. Pettis' striking is still very dangerous and Oliveira's has vulnerability to getting tagged and rocked.
I think as long as Pettis doesn't hold back and let Oliveira dictate the pace and land with more volume, he will be able to win the fight. Charles is a great grappler, but Pettis is no slouch with the takedown defense. He stifled many of Eddie's shots or worked his way right back up when taken down and Alvarez is a more skilled wrestler than Do Bronx for sure.