Four games into the season, rookie running back Wayne Gallman is more than ready to make his NFL debut. The Giants need him — badly.

They drag the league’s worst rushing offense into a game Sunday with the Buccaneers at Raymond James Stadium, an attack — we use the term loosely — that thus far has not included Gallman.

This looks as if it is about to change, and if Gallman gets on the field, he is confident he can make a difference.

“Of course,” Gallman told The Post on Thursday after practice. “There’s no doubt in my mind. I just know I can provide that spark for the offense, if need be.”

He could be needed now, not later. Orleans Darkwa came out of the loss in Philadelphia with a back injury and has not practiced this week. Shane Vereen came out of the same game with soreness and exacerbated a leg issue after reaching down for a pass Wednesday. Vereen did not practice at all Thursday.

While starting running back Paul Perkins is healthy, his production is sickly. Perkins is averaging 2.1 yards per rushing attempt, and in 23 attempts, his longest run has gone for 7 yards. There is no guarantee Darkwa and/or Vereen will be able to play. If that is the case, enter Gallman.

“He’s a young player who’s in his book, working on his fundamentals, and takes a step each week,” Ben McAdoo said.

The 6-foot Gallman is the tallest running back on the roster, and his upright, long-legged running style could get him in trouble in the faster-paced NFL. He is not a sharp-cut runner, but he is a powerful runner and has what scouts call “functional wiggle” to elude tackles. He started at Clemson in 2014 as a redshirt freshman and throughout his career often was overshadowed by teammates DeShaun Watson (now the quarterback of the Texans) and receiver Mike Williams (selected by the Chargers with the seventh-overall pick in the 2017 NFL Draft).

“I think he’s got a really good future,” running backs coach Craig Johnson said last week. “When you’re a young player and you’re trying to find your way, I’ve always believed that your team and your coaches see when you’re ready. I think that they’re starting to see that he’s doing some flashy things at practice, which is good. But you have to be ready and you don’t get the reps, so you just have to show up when you get put in there because he’s an ankle injury or whatever it may be from playing.”

As a fourth-round pick, Gallman was not nearly as heralded as other running backs in his draft class who are doing big things as rookies. First-round picks Dalvin Cook (second) and Leonard Fournette (seventh) are in the top 10 in rushing, and another rookie, Kareem Hunt (a third-round pick), leads the league with 401 rushing yards.

Gallman has been inactive in his first three games with the Giants, all losses, with the running attack last in the league, averaging 48.7 yards per game. Standing by and watching has been an adjustment.

“It’s been really tough,” Gallman said. “It’s been a learning process as well. There’s good and there’s bad that comes with it. Of course you want to play, of course you want to help support the team, but at the same time, you have to realize this is a new environment. This is something you have to learn mentally, not just physically, but there’s always that will and want to play and help out.”

Wearing sweats on the sideline during games, Gallman said he already notices big differences between what he came from and where he is now.

“The NFL is something completely new,” he said. “In college, you could do anything you wanted. In college, I could run left, run right and kind of get away with it. Up here, it’s about 10 times harder to do something like that. More so trusting your offensive line and actually running the play that’s called rather than doing something yourself.”

The past two days, Gallman estimated he received about 85 percent of the reps with the starting offense, with Vereen and Darkwa out and Perkins not given a full load in practice. Gallman could get the call, for the first time, Sunday. On Monday, he turns 23.

“That would be the best time of my life,” Gallman said. “Would be a dream come true.”