For three straight years, the Giants used either a first- or second-round pick on an offensive lineman. This year, they need that investment to start paying off.

Justin Pugh, Weston Richburg and Ereck Flowers all are returning to the starting lineup, and all at the same position they played last year. In the spring they were joined by John Jerry at right guard and Marshall Newhouse at right tackle. That was the alignment that played most of 2015.

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Right tackle is the spot the Giants would like to upgrade, whether that means bringing in a veteran to replace Newhouse or a starting left tackle and sliding Flowers to the right side. They have shown interest in free agent Eugene Monroe, a former first-round pick, and adding him certainly would solidify their bookend depth. It’s unclear which side he would play if he signs with the Giants.

Beyond the starting five that ended the spring workouts, though, there isn’t much proven depth. Second-year player Bobby Hart took reps at both right guard and right tackle during offseason workouts, but he worked mostly with the second group.

Canadian import Brett Jones is an intriguing story as the potential backup center and guard. Jones was the top lineman in the CFL before signing with the Giants last year and spending the season on injured reserve.

Adam Gettis, Byron Stingley and Emmett Cleary can be useful backups in a pinch, but the Giants would rather not go any long stretches with any of them in the lineup.

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Of course, they thought the same thing about Newhouse last year. He was signed as a sixth lineman, a reserve who could be versatile and patch up temporary holes. When Will Beatty was injured, the Giants wound up using that duct tape most of the season. They’d like a permanent solution going into 2016. Right now, though, that solution is unclear.