Luke Lewis, in his first game back for the 2018 Telstra Premiership season, was caught up in the free-flowing night of penalties at Southern Cross Group Stadium and is still scratching his head as to why.

He was sin-binned for allegedly tripping Billy Slater then seconds later getting entangled in Ryan Hoffman's legs in the spiteful 14-4 Cronulla Sharks win over Melbourne Storm.

Lewis missed the previous three rounds with a foot injury. Friday was his 100th game in Sharks colours – his 308th in the NRL.

Like Storm skipper Cameron Smith, who was also sin-binned on Friday night, he has never been sent to the sidelines for 10 minutes before.

"I don't think I've ever been sin-binned and I still don't know what for," Lewis said.

Replays showed Lewis didn't trip Slater but he and Hoffman struggled on the ground for too long, according to senior referee Matt Cecchin.

"I still don't know what I did. I think he tread on my foot and tripped over but I never grabbed him. It's what he (Cecchin) saw at the time but I don't think it was a sin-binning.

"I'm not too stressed about it. We won, so that's all that matters."