'Deadpool 2' Stars Ryan vs. Josh Whose Abs Ya Got?

8/4/2017 6:50 AM PDT

'Deadpool 2' Stars in Ripped Ab-Off, Ryan Reynolds vs. Josh Brolin

Ryan Reynolds and Josh Brolin are ABSolutely at war now over their sick "Deadpool 2" physiques ... thanks to the guy who got Ryan in rock hard condition.

Trainer Don Saladino threw down the challenge, telling Josh ... "You still have some work to do." He attached that statement to the ridiculous photo of Ryan's blood-splattered abdominals. It's definitely a direct response to the the pic Josh posted of his chiseled features ... major abs included.

Josh has been working out like a fiend for his role as the mutant, Cable, in the 'Deadpool' sequel -- and, to us, it seems ABsurd for anyone to say he needs more "work."

Still, the gauntlet's been thrown down. So, we gotta ask?