Sammy Watkins was a no-show at the Bills' voluntary workouts on Monday. (USATSI)

The Bills' voluntary offseason workouts opened up on Monday, but wide receiver Sammy Watkins was nowhere to be found. When reporters asked head coach Rex Ryan about Watkins' absence, they couldn't get an actual answer.

"I said I wasn't going to talk about anybody being here or not being here," Ryan said, per ESPN. Ryan had previously said, "We weren't 100 percent for attendance, but a couple of guys gave me phone calls, all that stuff."

The mystery might've been solved Tuesday morning, when Watkins posted a Facebook photo. Watkins appeared to be at a casino.

Here's a screenshot of that photo, via Watkins' Facebook page:

(Facebook: Sammy Watkins )

According to ESPN, those poker chips are from Harrah's Cherokee Casino, which is holding an event for the World Series of Poker in North Carolina. Someone at the event reportedly told ESPN that Watkins was in attendance on Monday night.

Watkins, the Bills' first-round pick in 2014, is coming off a 60-catch, 1,047-yard, and nine-touchdown season -- a year that didn't exactly go smoothly. Early in the season, Watkins complained to The Buffalo News about his lack of involvement in the offense.

"Everybody looks at you getting zero catches, zero yards but when you look on film 90 percent of the time you're open," Watkins said at the time. "I understand that these guys are young and they need some time to trust me. Once we get that trust, it'll be different. But for me, I need the ball at least 10 times -- I need 10 targets -- and I'll be fine with however many yards I get. And that's what I addressed in talking with my agent. We reached out to a couple people and tried to pull some strings like, 'Hey, I need my targets. You came up to draft me and I'm not getting targets -- that's a problem. You're making me look bad and you're making yourself look bad. Why not make both of us look good?'"

Watkins clearly had a point. Ryan even admitted in November that they needed to force the ball to their top playmaker.

Still, let's not overreact to this recent development, namely because it is only April and the season starts in September. And also because, as Ryan noted to reporters, the workouts are voluntary in nature.

With that being said, Watkins' absence and his Facebook photo do not make him look all too great.