The NFL Players Association announced on Saturday that it is not investigating the circumstances that led to Dolphins offensive tackle Jonathan Martin leaving the team last week.

A source claims Martin didn't leave the Dolphins because of bullying by teammates, but because of other emotional issues that caused the 2012 second-round pick to feel the need to take a break from football.

Martin's issues have been known within the franchise for a while, and are personal in nature, the source said. There is no set timetable for him to return to the team.

A media report had suggested that the NFLPA was going to investigate the role starting guard Richie Incognito may have played in Martin's decision to leave the team following a prank members of the offensive line played on Martin during the lunch hour.

The report claimed "bullying" played a role in Martin's exit, but the team has vehemently denied those accusations.

"We have an obligation to protect and support all of our members," the NFLPA's statement first obtained by NFL.com said. "We take official investigations very seriously and in this case, we have not launched an investigation into Richie Incognito or other players in Miami.

"The NFLPA believes that management has an obligation to ensure a safe and professional workplace and we will continue to be in close touch with our player leaders and all players involved as the information develops."

Martin left the Dolphins on Monday after a cafeteria prank had several teammates leave his lunch table as he sat down. He proceeded to smash his food tray and left the facility.

One teammate said Martin "just snapped," following the prank, which came a day after he allowed one of the team's six sacks the 27-17 loss to New England, which was his first start at right tackle this season.