The Pittsburgh Steelers suffered a tough 13-10 loss in an intra-division matchup against the Cleveland Browns on Sunday. After the game, running back Najee Harris voiced frustration in a cryptic fashion. His comments raise questions about the team's locker room during a pivotal stretch of its season.

“I'm just tired of this s**t,” Harris complained after the loss dropped Pittsburgh to 6-4 and third place in the AFC North, per The Athletic's Mark Kaboly. The back went on, hinting at some sort of discord among the team.

“There is just a lot of stuff that goes around that you guys don't see… I want to say what I really want to say, but it is difficult.”

Harris had a tough game individually against Cleveland's formidable defense. He earned just 35 yards on 12 carries.

Fellow running back Jaylen Warren, who was named the team's starting running back by coach Mike Tomlin ahead of the Steelers' Week 10 game against the Green Bay Packers, had a much more successful afternoon. Warren gashed the Browns defense for 129 yards on just nine carries. On a single carry, a 74-yard touchdown run, Warren outgained Harris.

Problems in Pittsburgh?

There have been hints of internal strife in Steel City this season. Earlier in the season, offensive tackle Chukwuma Okorafor was benched during a loss to the Jacksonville Jaguars for something “significant.”

George Pickens, Steelers, Steelers

Wide receiver George Pickens has raised eyebrows with social media activity that included scrubbing mentions of the Steelers on his Instagram account, and posting “free me” after a stretch of unproductive games. Fellow receiver Diontae Johnson got into a row with a coach on the sideline in Cleveland and had to be led away by a teammate.

Despite the winning record, the Steelers' offense is among the lowest-scoring in the NFL, and Harris is simply not producing. The frustration isn't entirely surprising. It will be interesting to see how Tomlin handles this latest round of irritation in his team's locker room.