LOS ANGELES -- The Los Angeles Rams' last three first-round selections could not have gone much better. With the 13th pick in 2014, they got the game's best interior lineman. With the 10th pick in 2015, they got one of the NFL's top running backs. With the first pick in 2016, they got their franchise quarterback.

Now it's time to start thinking about paying them.

Aaron Donald is the focus this offseason, but soon after that it will be Todd Gurley, and soon after that it will be Jared Goff. Donald, approaching the fifth-year option of his rookie contract, commands an extension that would make him the game's highest paid defensive player. But the Rams will negotiate that deal with a keen eye toward the two offensive stars who will follow.

"It does factor in," Rams general manager Les Snead said, "because you have to project in future years what you might have to pay them, and what that allows you to do is plan for the moment."

Snead said this during a phone conversation from the scouting combine in Indianapolis on Thursday morning. He hadn't yet met with Donald's representatives from CAA by that point, but he planned to. This week will mark the unofficial restart to their negotiations, tabled late last season because the Rams weren't necessarily close to meeting Donald's demands.

The Rams should be a lot more generous now, with Donald only a year away from potential free agency and coming off being named the NFL's Defensive Player of the Year. They have already budgeted for an astronomical contract. But they're also thinking about Gurley, who will have two years left on his rookie deal when the Rams exercise their fifth-year option for 2019. They also know that Goff is scheduled to be an unrestricted free agent in three years.

Gurley and Goff may not necessarily impact what the Rams are willing to pay Donald, because nothing short of a contract that sets the market on his side of the ball -- and potentially cuts into what some of the highest-paid quarterbacks make -- will be enough. But it will all impact how they fill out the rest of their roster, and it may affect what the Rams can offer pending free agents such as Sammy Watkins, Lamarcus Joyner and Trumaine Johnson.

Snead painted the picture this way: "We can’t go into the candy shop and buy all the candy, because we’ve still got dinner a little later down the road."

In other words, the Rams can't just sign players based on how they fit under the current cap.

"If you did do that, what that would do is it affects your ability to get things done with those players," Snead said. "Everything’s a domino effect."

Donald, Gurley and Goff are in line to cost $18.9 million toward the 2018 salary cap, which represents only 10.6 percent of the projected limit. But Donald, whose 2018 cap number would increase if he signs a new deal this year, should average at least $20 million on an extension. Gurley's extension, which will be influenced largely by what Le'Veon Bell gets this spring, could reach about $12 million a year. Goff's extension, affected by an offseason when Matt Ryan and Aaron Rodgers could tip the scales of the quarterback market, may average $25 million when his turn comes up.

Soon -- perhaps by 2020 or 2021 -- Donald, Gurley and Goff could absorb up to one third of the Rams' salary cap.

Question is: Is that sustainable?

Snead believes so. He referenced the recent Indianapolis Colts, who won 37 games in a three-year stretch from 2006 to 2008 despite tying a significant amount of their cap space to a quarterback (Peyton Manning) and two receivers (Marvin Harrison and Reggie Wayne).

"They had a philosophy -- they were going to do it with offense -- but they had to have a real good plan to how they were going to get it done on defense," Snead said. "... It’s easier to talk about, harder to achieve. But I think that’s what we have to do over these next few years. We’ve got a defensive player, then we’ve got an offensive player, then we’ve got a QB. But there’s 19 other starters, so, what’s going to be the philosophy? How are we going to get it done? That’s what we’re doing now."

Teams have certainly shown they can win with a top-heavy payroll. From 2012 to 2017, 17 teams had three players absorb at least 30 percent of their cap space. Those teams combined to go 153-109-4. Three of those teams had their top three players make up more than 34 percent. The 2012 Denver Broncos (with Manning, Elvis Dumervil and Champ Bailey) went 13-3 and the 2014 Detroit Lions (with Matthew Stafford, Ndamukong Suh and Calvin Johnson) went 11-5. But the 2012 St. Louis Rams (with Chris Long, Sam Bradford and Steven Jackson) went 7-8-1.

A lot has changed for the Rams since then.

"It took a few years to build, but now we feel like, all right, we have tipped," Snead said, "and because we have a young stable of players, we feel like we can sustain success -- or we have an opportunity to, depending on many factors."

Those factors will consist of how well they draft, the values they find in free agency and, as was the case with All-Pro cornerback Marcus Peters, whether they can acquire elite, affordable players via trade. Those elements become heightened with expensive star players taking up so much cap room, but that is a burden the Rams are happy to take on.

"There’s an element of how you utilize the salary cap and the draft and player acquisitions when you’re building," Snead said, "and then there’s how you use it when you tip toward being in a window."

The Rams are clearly in a contending window, but it won't last long if they don't keep their core pieces in place. Donald, already a two-time first-team All-Pro, and Gurley, who nearly won last season's MVP, are on track to set the market at their respective positions. Goff, who made the Pro Bowl at 23 years old, probably won't set the bar at quarterback, but he should eventually be near the top regardless.

Snead prefers to "let that play out," specifically with Gurley and Goff.

"But it is somewhat playing out in chronological order."