The 20-year-old was brought in as injury cover for Josh McFadden last month, and described as "undoubtedly a prospect" by the club.
The former Latvian U20 international, who has played in Russia and Slovakia, didn't make the grade in the UK though.
Coach Tom Barrasso told The Star: "Seleckis has been released. He was not close to being prepared for the level of play in the EIHL."
He dressed six times for the South Yorkshire club.
It looks like Steelers, who have desperately been trying to find a replacement for injured defenceman Mark Matheson, will be facing Nottingham Panthers on Saturday with five regular d-men and apprentice Jordan Griffin.
They won't have triallist goalie Carsen Chubak available either.
"Carsen is making progress with his game, but it is early days for him still" said the coach.
However, there is good news up front as Barrasso has high hopes of a return of fifth-top scorer Robert Dowd.
"I am optimistic on Dowd, but not certain at this time. We should have a better idea by Friday."
Barrasso believes his men are focused on scrapping for every available point, with a place in the end of season Play Offs the prize.
"Our training is solely focused on building to be prepared for Saturday” he said.
“We are keenly aware of the importance of every point we are playing for. I like where we are at as a group at the moment."
A win for Sheffield at Nottingham would be their third on the bounce.
Panthers are nine points and three places ahead of them in the standings.
Cardiff Devils lead the EIHL pack, a point ahead of Belfast Giants, with a game in hand.
*Steelers’ Jackson Whistle is the Elite Ice Hockey League’s Player of Week.
The Steelers’ netminder played a vital part in his team's wins last weekend and stopped all bar three of 72 shots.*