That includes one of each in the 32-22 loss at Wigan Warriors two days ago.
Mahe Founa was controversially sin-binned just before half-time for an alleged late hit on Jai Field and Tigers had Brad Martin sent-off following a high tackle on Willie Isa in the closing minutes.
Both players will have to wait until the RFL’s match review panel meets on Monday to hear if they have been charged and will miss the Betfred Challenge Cup derby at Leeds Rhinos a week today.
Wigan scored two converted tries while Fonua was off the field, which effectively proved a match-winning spell.
But after trailing 28-6, Tigers narrowed the gap to six points before Martin’s red card handed the initiative back to the hosts.
Tigers were left on just one win with almost a quarter of the season completed.
That victory came against Hull two weeks ago, when they kept 13 men on the field throughout.
Reflecting on the loss at Wigan, Hepi said: “I think the boys dug deep.
“We were a few men down, a few cards got handed out, which seems to be a common occurrence for us lately.
“I think if we sort those out I think we are not far from turning a lot of these teams over.”
This season has seen a spate of red and yellow cards across Super League and Hepi reckons some, including the one shown to Fonua, were “questionable”.
“Without going after the rule changes too much, it is just happening week on week,” said the New Zealand forward.
“I think it [Fonua’s card] was a bit harsh, it is happening a bit too often.”