Tuesday, September 6, 2011 11:55 am

The NFL Draft is just one team-building vehicle. Keep this in mind when assessing the Rams overhaul for 2012.

Free agency is a major tool for fortifying the roster. Trading is another solid option. The well-run teams fill holes via the waiver wire, making roster adjustments on the fly.

Good general managers raid practice squads and find talent among the ranks of unemployed players rotating through their facilities during weekly cattle calls.

Alert GMs even find gems among the lowest personnel form, the “street free agents” that arrive at training camp as the longest of longshots.

Fans zero in on the draft because it is on TV. The NFL has turned the event into a marathon of speculative analysis.

But there are many ways to upgrade a team, as Rams general manager Billy Devaney has proved over the past few years.

So what if a street free agent like Danario Alexander bumps notable draft picks like Donnie Avery and Mardy Gilyard out of jobs at the final preseason cutdown?

The idea is to build the best team by all means possible. This is a 12-month process, since GMs never really quit looking for players.

The Rams wide receiver scenario offers a classic example of “all means necessary."

Devaney plucked Danny Amendola off the Eagles practice squad. Many fans ridiculed his ascension to the lead receiver role here last season -– given his humble beginnings -- but Amendola can play. Nobody drafted him coming out of Texas Tech, but his lack of pedigree means nothing now.

The Rams won a Super Bowl with undrafted players leading the way on both sides of the ball.

Brandon Gibson came to the Rams from the Eagles with a fifth-round pick for linebacker Will Witherspoon. Fans continued to pile on this trade well into last season, until Gibson emerged as a viable target for Sam Bradford. Gibson’s stellar preseason work eased concerns about his 2010 inconsistency and earned him a front-line role starting this season.

So what if two of the top three Rams receivers are Philly castoffs? Their performance matters, not their origin.

Mark Clayton arrived from the Ravens for an inconsequential draft pick and starred last season before suffering a catastrophic knee injury. As the preseason wound down, the Rams re-signed him and put him on the Physically Unable to Perform shelf.

His success with Bradford last season suggests he will provide a big second-half lift this season.

Alexander went undrafted last year because of his oft-repaired knee. The Rams expected to hold him out of action last season, but he worked his way into the lineup and flashed big-time potential. The Rams suggested he undergo a sixth procedure on his bad knee this summer, but he played on to earn a job.

There is no telling if he will hold up, but DX has already done more than many receivers this franchise drafted in the middle rounds over the years.

Mike Sims-Walker arrived as a mid-level free agent this summer. Fans clamored for a sexier signing, like Plaxico Burress or Chad Ochocinco, but Devaney opted for solid instead. Walker caught 14 TD passes the last two years in Jacksonville and should provide Bradford some reliability in the red zone.

Greg Salas arrived as a fourth-round draft pick. The Rams had him rated neck and neck with Austin Pettis, their third-round pick. The front office did not plan to hit the same position with consecutive picks. But when Salas was there in the next round, Devaney grabbed him and endured the catcalls of critics.

Salas repaid that faith. He outperformed Pettis during the preseason and moved into contention for some serious work in this offense.

Did Pettis get a free pass this summer because of his draft status? Given his nearly non-existent role in preseason games, you can draw that conclusion.

But the Rams braintrust factored the lost offseason of work due to the lockout, sized up his potential and granted him additional time to prove himself.

Fans may blast Devaney for his spotty draft record on receivers, but the bottom line is this: The 2011 group is a significant upgrade from the year before.

Bradford is happy. New offensive coordinator Josh McDaniels is happy.

If the draftniks aren’t happy, well, the Rams can live with that as long as these guys perform as expected.