Cooper, who bagged two wickets in his four-over spell in a five-wicket defeat that saw Rajasthan lose the play-off spot to Mumbai, was reported by on-field umpires Rod Tucker and K Srinath, along with third umpire S Ravi, at the conclusion of the match.
The Trinidad and Tobago pacer was the most economical of the Rajasthan bowlers -- 9.50 -- that saw a Corey Anderson (unbeaten 44-ball 95) blitzkrieg help Mumbai get to their 190-run target in 14.4 overs.
However, pending any clearance by the committee, Cooper would be available for Rajasthan selection in the next edition of the cash-rich league but if he is reported a second time, he would be suspended from bowling for the remainder of that season.
Cooper's bowling action first came under the scanner in January 2011 when he went to the University of Western Australia to undergo tests and undertake remedial work to correct the fault.