Training camp is already taking a toll on the Pittsburgh Steelers. The team saw superstar wide receiver Antonio Brown go down with an injury on Thursday.

According to head coach Mike Tomlin, Brown is being evaluated for his injury which remains undisclosed at this point in time, via NFL.com.

Antonio Brown is out of commission, though the cause is unclear.

Steelers coach Mike Tomlin told reporters Thursday the team sent Brown from the team's camp in Latrobe, Pennsylvania, to Pittsburgh for evaluation for an unspecified injury.

Brown is without a doubt the Steelers best offensive player. Although Ben Roethlisberger has led the team to two Super Bowls and Le'Veon Bell is arguably among the league's elite running backs, few would dispute Brown's case as the best wideout in the NFL today.

With that being said, losing Brown to an injury would be devastating to the team's chances of being a legitimate title contender in the AFC. Fortunately for Pittsburgh, the undisclosed injury appears to be minor with the perennial All-Pro expected to be out only a few days, via ESPN's Adam Schefter.

Pittsburgh is currently considered to be one of the heavyweights in the AFC and perhaps the biggest threat to Tom Brady's New England Patriots aside from the defensive-minded Jacksonville Jaguars. It would be a different situation entirely without a health Brown on the field from week to week.

The fact that this is an undisclosed injury is perhaps the most concerning. If it is something that he can bounce back quickly from in a matter of days, then why not disclose his health issue.