Attendance will be high this week at the Giants’ minicamp, but if Ereck Flowers is not on the field, it will be difficult to keep the focus on the players participating and not dwell on who is missing.

The offseason workout program is two weeks old and Flowers has yet to show up. This is puzzling to the entire organization and it is a source of irritation to the new regime of general manager Dave Gettleman and head coach Pat Shurmur. Teams cannot make a big deal about attendance this time of year — the program and the three-day camp that starts Tuesday are voluntary — but it is expected that all or close to every player decides to volunteer to be in the building.

Odell Beckham Jr. attended the first week of the program but not the second. He is not cleared medically, coming off surgery to repair a broken ankle and will not be able to participate in this camp, if he attends.

Last offseason Flowers was widely praised for practically living at the team facility, with the previous Giants coaching staff taking note of his diligence. Flowers started 15 games at left tackle and showed improvement, but only in comparison to his performance the previous two years, which was severely lacking.

Already, Shurmur informed Flowers he is no longer the left tackle, as Nate Solder was signed (for $62 million) to take over as Eli Manning’s blind-side protector. Flowers is moving to the right side, competing for a starting spot, initially at tackle.

“We’re hopeful he’s one of our best five guys,’’ Shurmur said a few weeks ago at the owners’ meetings, offering no other guarantees to Flowers during a phone conversation Shurmur said was “respectful, and he understood, and he told me he looked forward to getting back to work.’’

Flowers is yet to report back to work, at least not within eyeshot of the Giants. If he is a no-show at this minicamp — the Giants have no reason to believe he will attend — irritation could turn into something more serious, especially if Friday night, the Giants select a player in the second or third round of the draft they believe can immediately compete for the starting right tackle job. That is unlikely, given this suspect crop of offensive tackles, but not impossible, if the Giants see Mike McGlinchey (Notre Dame) — if he is there at No. 34 — or Kolton Miller (UCLA), Brian O’Neill (Pittsburgh), Tyrell Crosby (Oregon) or another tackle prospect as a possible rookie starter.

It is doubtful anyone on the current roster qualifies. Undrafted Chad Wheeler started four games at right tackle as a rookie.

The Giants are not at the point they are looking to jettison Flowers, but they would like him to actually start competing for a job. They would not get much for him, anyway, if they tried to deal him. He is entering the final year of his four-year contract, with a base salary of $2.39 million, with a salary cap hit of $4.5 million. There is no scenario in which the Giants commit to Flowers by picking up his fifth-year option of $12.5 million for the 2019 season, a decision that must be made by May 3. If they do, it would only be for the purpose of securing his spot on the roster, as they could cut him before next season and wipe the entire cap hit off the books.

This week’s non-contact camp is not going to settle anything about anyone, as far as changing the way the Giants think heading into the draft. But there is no doubt it behooves certain players to make a positive on-field impression with the new staff. Running back Wayne Gallman had a promising (4.3 yards per carry) showing as a rookie, but nothing he does this week would distract the Giants from taking Saquon Barkley with the No. 2 overall pick. If the new coaches like Gallman, though, it could steer the Giants away from a running back in the second round, if they go for someone other than Barkley in the first round. Quarterback Davis Webb did not get a single regular-season snap as a rookie and will get plenty in these next three days. He could turn some heads in this camp, but if the Giants are sold on a quarterback (it is believed they are not), they will take him, Davis’ showing notwithstanding.

Most of all, Flowers would help his case simply by showing up. Perhaps he is waiting to make an entrance on Wednesday for his 24th birthday. He could get a cake and get to work.