The Buccaneers have two of the best rookies this preseason

The Tampa Bay Buccaneers have two of the best rookies at their positions this preseason, according to Pro Football Focus. One of them is, of course, Vernon Hargreaves -- he of two interceptions, one more defensed pass and a whole lot of being around the ball. He's the best-graded cornerback in the 2016 NFL preseason so far. Good fun.

The other player is....fourth-string tight end Alan Cross, apparently? What?

Hey Rookies,

Welcome to the NFL . Keep up the good work! pic.twitter.com/VEX40dpTxM

— Pro Football Focus (@PFF) August 23, 2016

Cross has all of one catch this preseason, so it's not like he's actually standing out going against all of the backups of the backups. Except, I guess, as a blocker. Which presents one amusing possibility: Cross might beat out sixth-round pick Dan Vitale, who hasn't stood out this season. Unlikely, but possible.

Mostly, this is a really good reminder to take players' performances against third-string backups with a grain of salt. It's also a good reminder that Pro Football Focus' grading does not take opponent quality into account whatsoever.