Updated

Northwestern running back Venric Mark says he is not sure all his teammates who signed union cards in January realized the ramifications.

Mark says some players signed, some did not. He wonders if those who did "knew what they were or if they thought it was going to turn out the way it did."

A regional director of the National Labor Relations Board ruled last week that the Northwestern football team can form what would be the nation's first union for college athletes. The school is appealing.

Mark, who would not say if he signed, spoke Tuesday as Northwestern resumed spring practices following about a two-week layoff.