You can deduce though.
Their coaching staff stated that they would use all three in a RBBC.
When the Jets had 3 RBs last year, all three played (annoying at it was to the rest of us). It was a 39%/35%/26% split so the coaching staff didn't lie.
Since last season, their OC left, but was replaced by Bates who was already on the staff and still under the same Head Coach.
The Jets RB coach raved about McGuire. Somehow he compared his skillset to LT.
https://jetswire.usatoday.com/2018/06/15/jets-rb-coach-compares-elijah-mcguire-to-ladainian-tomlinson/
After McGuire broke his foot, the Jets stated that he would be back this season. He's been practicing for 2 weeks and should be activated next week.
In game 1 of 2018, the Jets gave Powell and Crowell 40% of the snaps each and Cannon 20%. Cannon looked awful and got only
1 snap the next 4 weeks combined. He then got 3 snaps in week 6 and was forced to play 23 snaps last week after Powell got hurt. Not to mention that Crowell has been dinged up for the past couple of weeks.
Cannon is not an all-around RB like Crowell or McGuire. His skill-set is speed in open areas. They might scheme up some plays for him, but he's not very good in between the tackles. He needs space. His scouting reports stated that he wasn't a natural pass-catcher either.
I don't see him getting a lot of snaps once McGuire comes back. Some drawn up runs to the outside or catches in space. Maybe some mop up time. Now tomorrow might be a different story since McGuire isn't eligible to come back until the following week. They also brought up Henderson for tomorrow. Henderson is the one to watch. He could find himself into a 4-man rotation if the Jets want to have 4 active (which is what it seemed they would do before McGuire got hurt).
In the second half of the season, I would guess something like 45% to Crowell, 35-40% to McGuire, and 15%-20% for Cannon/Henderson. You're right though, no one knows right now for sure. I could be wrong. Just my guess.