Discerning cues about which signal-caller resides in the back-up role behind starting LSU quarterback Zach Mettenberger is laden with noting subtle cues on the fields at the Charles McClendon Practice Facility.

Noting whether freshman Anthony Jennings overstrides on a deep out to the sideline.

Parsing coach Les Miles critiques of early enrollee Hayden Rettig’s cadences at the line.

And charting whether sophomore Stephen Rivers’ overall accuracy isn’t flagging.

Assessing the race ahead of a 2 p.m. kickoff for today’s spring game at Tiger Stadium is akin to purchasing home owners insurance. The decision is critical, but its flaws only apparent after a pipe bursts and floods the basement. Simply put, a seemingly innocuous position battle in spring gets magnified in the grind of a pass through the Southeastern Conference.

Right now, though, the three contenders seem less like a team of rivals than a trio simply putting each other through the requisite paces over 15 practices and ahead of a final assessment in August.

“We’re always looking to make the person in front of us better,” said Rivers, who is 10 of 25 passing for 109 yards this spring. “We know that Zach’s got that spot right now. By no means are we just giving up, but in our minds we’re improving our games every day. The better we get, the better he gets.”

So, if fans can’t look forward to seeing a souped up aerial attack, they’ll have to settle for the vagaries of debating who is No. 2 on the depth chart behind Mettenberger, who has thrown for 723 yards and nine touchdowns against two interceptions with a 61.5 percent completion rate in scrimmages.

Even then, Jennings appears to have nudged into the lead to be the most popular man in Baton Rouge — the quarterback purple-and-gold clad masses holler to insert upon the first signs of sputtering starter.

Since practices opened last month, Miles hasn’t been hesitant to praise the 6-3, 205-pound product out of Marietta, Ga., and an Elite 11 camp alum. The ninth-year coach has spoken of inserting Jennings, tabbed a dual-threat quarterback, situationally into packages that capitalize on his mobility — a trait coveted by Miles.

“Understand this, when it starts getting crowded back there in that pocket, and you have a quarterback that’s able to escape, everybody likes that,” Miles said.

Pigeonholing Jennings is a risk, too. Ahead of his senior season, he won MVP honors at an Elite 11 camp in Georgia, and passed for a respectable 2,187 yards an 19 touchdowns and only threw four interceptions.

If Jennings can look robotic throwing the football, it belies sound footwork that sets a firm base and only overstrides occasionally. His delivery is consistent, and a velocity balanced with touch on out, corner and deep curl routes. Over three scrimmages, he’s passed for 168 yards and three touchdowns and tallied a 132.3 quarterback rating.

“Anthony’s certainly shown poise for a freshman,” Miles said. “His ability to understand the offense — throw it and read it — and understand what we’re trying to accomplish, plus the mobility he has are obvious advantages.”

Only Jennings can’t comment, given the team policy putting the kibosh on freshmen speaking to the media. So it falls to Rivers to praise his peer.

“Anthony has done a great job,” Rivers said. “You can tell he’s been to the Elite 11. He just hops in there, and you can tell he has what you need to be a quarterback. He forgets about the last play. He’s doing great.”

As for Rettig, a 6-3, 201-pound product from Los Angeles Cathedral, his transition has been slightly stilted despite entering as the nation’s No. 3 pro-style prospect. While he might not be as mobile as Jennings, his timing arm strength are pluses. In scrimmages, he’s thrown for 158 yards on 8 of 15 passing ­ — half the throws compared to Jennings — but has three touchdowns and a 207.8 passer rating.

Yet prep scouts noted a need for better footwork at the top of his drop, and occasionally letting his hands sink loading up for a throw. Those tendency still nag at Rettig, while he’s also in the midst of transitioning from a Spread system to LSU’s pro-style set.

“He comes from a very different offense, where it it’s in the gun and throw every down,” Miles said. “Now’s he having to hand off, and cadence is an issue. There’s some more work for him to do. His preparation coming into college is not exactly what we do. It’ll just take some time.”

A looming questions is whether the timetable matches up to the one imposed by the coaching staff. And whether he Rivers and Rettig can close any gap.

‘We’re just trying to go out and execute what we have in right now,” Rivers said. “We want to go out and do the best we can. It’s not really a work day, but more of a preparation day. It’s more of a show off day, getting the things we’ve doing for 15 practices down pat.”