On one hand, the Raiders are 9-0 in games in which he catches a touchdown pass.
On the other, Roberts led the NFL in dropped passes last season with 13, per Associated Press, while ESPN Stats & Information had Roberts with seven drops.
Roberts also might be the team's toughest wideout. He said this week in training camp that he played last season with a double sports hernia, an injury, he said, he suffered in in the 2016 training camp. Perhaps it makes the drops more understandable; perhaps it makes his 38 receptions for 397 yards and five TDs last year more commendable.
"Sometimes you've got to do that, man," Roberts said this week of playing through the pain. "It is what it is. I'm healed up now and looking forward to this season.
"It was more mental. When your body isn't all the way how you want it to be or need it to be on game day, I might think I've missed a step. So it's really a lot going on mentally."
Roberts, who had 32 catches for 480 yards and five TDs as an undrafted rookie in 2015, did not miss a game in 2016 nor did he ever appear on an injury report, though his production tailed off in the second half of the season.
Raiders coach Jack Del Rio said Roberts' injury was "news to me" after having a talk with him this week.
"I certainly appreciate guys that find a way to be out there for their team and their teammates," Del Rio said. "We had a couple tremendous illustrations of what it looked like when Charles Woodson was here and the way he gutted it out and played through things. I think that legacy lives on a little bit now with some guys toughing it out. That's good stuff.
"Now, we want them to be smart. I'd like them to report anything they had, but I respect his decision to keep it to himself and just play."
Del Rio said the only off-the-field development he knew of Roberts dealing with last season was the birth of his first child.
"A newborn can disrupt your sleep patterns at home," Del Rio said with a grin. "To me, that was something I was concerned about last year. Little baby is growing and he has that other issue resolved, so we'll look forward to him having a great year."
After his walk-off 41-yard touchdown catch and run in overtime at the Tampa Bay Buccaneers in Week 8, Roberts did not have another score.
"It was tough, mentally," Roberts said. "I just had to stay in it. It was a real struggle, but I made it happen. I got through the season. It wasn't my best and I didn't feel my best but I made it happen. I had to do it."
Even without, as he said, any semblance of core strength.
"When your body's not right," Roberts said, "your head's not right."
Not that quarterback Derek Carr agrees, mind you.
"I don't know why he goes under the radar so much," Carr said, "but that man has made game-winning catch after big-time play and all these things and it's because he works his tail off. There's no secret. This man goes out there every single day. He puts in the extra work when nobody is watching. He studies his stuff, and he asks me questions."
Roberts said he underwent surgery on Jan. 31, and is looking to truly break out this season.
"They need to know who I am," Roberts said with a big grin. "I ain't with that flying-under-the-radar [business]. I'm trying to make it happen. I've got a family to provide for."