No, it's pretty clearly spelled out that he does have that power. It's right there in the CBA.
"When a player is guilty of any other form of conduct reasonably judged
by the League Commissioner to be detrimental to the League or profes-
sional football, the Commissioner will have the right, but only after giving
Player the opportunity for a hearing at which he may be represented by
counsel of his choice, to fine Player in a reasonable amount; to suspend
Player for a period certain or indefinitely; and/or to terminate this
contract"...