Rhinos moved a step closer safety with a dramatic 18-16 win over Salford Red Devils on Friday night.
A victory at Halifax next weekend could make Rhinos secure, depending on other results and Sinfield hopes then to move ahead with bringing players in for 2019.
Sinfield rejoined Rhinos at the start of July and revealed recruitment for next year has been on-going since the middle of that month.
He said: “I suppose we are waiting to press the button on one or two.
“When we are 100 per cent safe and we know where we’re at, that’s the point we can do it.
“At the moment we are not 100 per cent safe, but hopefully then we can move pretty quickly.”
Rhinos led by six points twice on Friday night only to see Salford draw level each time and the visitors had a late drop goal attempt charged down before Liam Sutcliffe landed the winning penalty with the last kick of the game.
Reflecting on Leeds’ second victory in six days, Sinfield said: “A win’s a win, that’s the best way to sum it up.
“Both teams were edgy, I think that’s because of the competition and how it’s structured.
“Both teams were trying not to lose the game, rather than win it.
“Thankfully we had enough in the end just to get through.
“I think we would have lost that game eight weeks ago. I’m delighted with the two points, it was a huge effort from our guys.
“We were dumb at times, some of the errors at the start of the second half you scratch your head at and think ‘what on earth are we doing’, but we found a way to win and that’s a real good sign.”
Sinfield praised his group for being “willing to work for each other and graft and fight”.
He added: “Although we do some dumb things with the ball at times, defensively I think we are improving.”
Sinfield reckons Rhinos will need at least one more win to be safe, but is targeting two.
He said: “Some of the Championship sides who’ve stepped up already, I suspect they will get some scalps.
“I think Halifax at some stage will get somebody so with that threat we won’t be complacent at all.
“I like the way Richard Marshall and his team operate.
“I watched Halifax earlier this year and they play some decent stuff.
“It has always been a tough place for Leeds to go. I remember going there in the early 2000s and it was a real fortress for them so we will look forward to it.
“It brings a new challenge then we finish with Toronto at home. It can be a great two weeks for us as a club and a team or we can make it really, really difficult for ourselves.
“Hopefully we choose the first one.”