James Harrison says it ain't just Big Ben and the Steelers' D causing problems in Pittsburgh ... 'cause the legendary LB tells TMZ Sports it's time start pointing fingers at Mike Tomlin as well.
"I think now, a lot of it has to be put on to what the game plan is -- the coaching."
Tomlin's been Teflon in Pitt -- the dude does have a Super Bowl ring -- but a lot of people ... including Terry Bradshaw himself ... have grown tired of seein' him as head man.
Doesn't seem James is quite at that point yet -- but the ex-Steeler does tell us the coaching DEFINITELY needs to improve if Pittsburgh wants to end its 3-game losing skid.
"Now it's actually where you gotta kick it in -- and EVERYBODY has to be held accountable. From the top down."
Tomlin and the staff better get going quickly ... the Steelers have Tom Brady and Bill Belichick this week.
Good luck!!