The New York Giants hold a pre-draft mini camp

New Giants fullback Will Johnson could be a valuable offensive weapon this season. (John Munson | NJ Advance Media for NJ.com)

Will Johnson was one of the Giants' least-heralded free agent signings this offseason.

He also might be their most intriguing.

The Giants signed Johnson, who has one of the best backstories in the NFL, away from the Pittsburgh Steelers early in April. And while he is listed as a fullback on the roster currently, that is only the beginning of the impact he could have on the Giants in 2016, both in terms of on-field production and roster construction.

The versatile Johnson saw his role in the Steelers' offense greatly diminished in 2015. He played 89 offensive snaps, 10 of which were in victory formations, according to Steelers Depot. Johnson had just six touches, and was inactive for Pittsburgh's playoff loss to eventual Super Bowl champion Denver.

But in studying the film of several Steelers games from last season, it is obvious Johnson has the versatility to play several roles for the Giants in 2016. Here's a look at three positions Johnson could potentially fill for the Giants this season:

Fullback. Johnson started his career as a true fullback, but he played just two snaps at fullback last season, per Steelers Depot. But if the Giants were to use him as a fullback, his snap count would definitely make a big jump. Nikita Whitlock was used as a fullback in under 12 percent of the Giants' offensive plays in 2015, but that was still good enough to give him nearly 50 percent more snaps than Johnson had in total (132 for Whitlock, 89 for Johnson).

It's hard to make any definitive statements about the Giants' roster situation in May. But Johnson, on paper, should give the Giants an upgrade at fullback. If they use him strictly at that position, he could bring a noticeable change to how the Giants run their offense. But Johnson can also do more.

Tight end. Johnson lined up with his hand on the ground pretty frequently for the Steelers last year, and he also would play on the wing off the line of scrimmage, occasionally going in motion, as the Giants frequently do with their tight ends.

Johnson was not much of a factor in their passing attack, but he can get open in the middle of the field. Johnson had two catches (four targets) for 16 yards in 2015, as well as a two-point conversion catch.

What Johnson also can do: Block. In the snaps I watched, I never saw him get overpowered or allow a play to be blown up. Granted, the Steelers ran away from his side multiple times, but they also ran right behind him with success.

One example that stood out: He had a key block to help spring Le'Veon Bell to a 21-yard run in the fourth quarter of Pittsburgh's Week 4 win over Baltimore, getting to the second level and smothering Ravens linebacker Daryl Smith as Bell ran right off his butt (and another lead block from tight end Heath Miller).

How the Giants use (or don't use) Johnson as a tight end is another puzzle piece to their ultimate roster decisions. It's no secret they struggled with blocking at the position last year once Daniel Fells was lost. That just has not been a strong suit for

. Rookie

can block, but his playing time might be limited as he adjusts to the passing tree. The Giants also believe

can be a blocker, but he is another young player who needs to prove it. Johnson could be their answer.

If Johnson is going to play tight end with any regularity, that might narrow the number of tight ends the Giants carry. But if he is going to be strictly a fullback, keeping four tight ends is not out of the question.

Short yardage tailback. This is likely a long shot, but it's noteworthy. Johnson carried the ball four times last season, all in the Steelers' season-opening loss to the Patriots. The stats were nothing to write home about, as he had just seven yards rushing (1.8 per carry). But three of those carries came down on the goal line behind a fullback, and Johnson punched one in for a 1-yard touchdown run.

Johnson also received a carry out of the shotgun early in that game, a draw. He gained six yards, and showed he could hit the hole hard and with some vision. The play was also extremely well-blocked.

TALK IS CHEAP, Ep. 53: How Giants can improve roster before training camp

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James Kratch can be reached at jkratch@njadvancemedia.com or by leaving a note in the comments below. Follow him on Twitter @JamesKratch. Find and like NJ.com Giants on Facebook.