The Rams made the headline-grabbing trade to solidify the quarterback position for years to come.

No, not last week’s historic blockbuster deal that moved the Rams to the top of this year’s draft and put them in position to select North Dakota State’s Carson Wentz or California’s Jared Goff.

They could not have completed that trade if not for another high-profile deal that did not turn out according to plan.

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In March 2015, the Rams and Philadelphia Eagles swapped quarterbacks. The Rams sent Sam Bradford, the No. 1 pick in 2010, to the Eagles for Nick Foles. As part of the deal, the Rams also received a second-round pick this year.

Foles signed a $24.5-million extension and opened last season as the starter. But he was benched after nine games and replaced by journeyman Case Keenum, a situation that ultimately led to the trade with the Tennessee Titans for this year’s No. 1 pick.

The Rams gave up their No. 15 pick, as well and two second-round picks, a third-round pick and first- and third-rounds picks next year.

And it was the extra second-round selection the Rams acquired in the Foles trade that positioned them to fend off other suitors, which reportedly included the Eagles, for the top pick held by the Titans.

“That’s really the only reason that we were able to do that, is because we had the multiple twos,” Rams Coach Jeff Fisher said.

Gil Brandt, a former Dallas Cowboys executive and longtime draft analyst, concurred.

“When you’ve got two teams going against each other the price goes up,” Brandt said. “The thing that hurt Philadelphia was they didn’t have the second-round picks like the Rams did.”

Wentz or Goff will join a Rams team that currently has three quarterbacks on the roster: Keenum, Foles and Sean Mannion.

One of them could be traded — which might enable the Rams to re-stock draft picks — or released.

Rams General Manager Les Snead declined to specify which quarterback could go on the trading block other than saying a trade was “something we’d have to look at.”

In March, the Rams offered restricted free agent Keenum the first-round tender of about $3.6 million, a move made to ward off other suitors. If Keenum receives an offer sheet, and the Rams choose not to match it, the Rams would be awarded a first-round draft pick as compensation. The deadline for restricted agents to sign offer sheets is April 22.

If Keenum signs the tender, his salary could make him attractive to potential trade partners, and he might generate more in return than Foles. But Keenum is the presumptive starter going into the off-season program and Mannion is regarded as a prospect the Rams can continue to develop.

So Foles’ future with the Rams is probably the most uncertain.

The Rams made the trade with the Titans anticipating that their number of 2017 draft slots would increase based on compensation picks they could receive for the departures of free-agent cornerback Janoris Jenkins and safety Rodney McLeod. Snead noted that draft picks “are currency and we’re all greedy to an extent…. We like to have things in the bank.”

“You could project that you might get a third-rounder,” Snead said. “There’s no guarantee, but that played a part in it and we even wrote that in the way the trade was, that they would get the comp pick instead of the real pick.”

Follow Gary Klein on Twitter @latimesklein