The return of Ron Erhardt

Ron Erhardt? That question struck some National Football League-watchers, surprised to find New England's deposed head coach hired as offensive coordinator of the New York Giants.

Just to review: New England canned Erhardt after the Patriots wound up winning only two of 16 games this season. The Giants, meanwhile, made the playoffs for the first time since 1963.

Despite New England's dismal record, Erhardt never lost the respect of many football insiders.They consider him a a victim of circumstance, a competent and popular football man caught in the quicksand surrounding the Patriot franchise.

After he was fired, several clubs were at his doorstep, but Erhardt chose the Giants. He had worked alongside Coach Ray Perkins when both were assistants with New England. In 1978, the Patriot offense was the NFL's most productive under Erhardt.

His most difficult task with New York may be to select a starting quarterback between Phil Simms and Scott Brunner. He faced the same challenge in New England , where Steve Grogan and Matt Cavanaugh vied for the job.

To Erhardt's credit, the Patriots were seldom out of any game during the past season. In fact, their average margin of defeat was less than a touchdown, and they lost in the last minutes several times. By contrast, Baltimore lost by nearly 20 points a game in compiling an identical record. New England earned the ''worst in the league'' designation, however, because Baltimore bookended its campaign with victories over the Patriots.

Erhardt, who hopes that someday he'll be an NFL head coach again, cites his three-year mark of 21-27. Bill Walsh has the same record in San Francisco. Only thing is, Walsh's club, the new Super Bowl champs, got better, while Erhardt's collapsed.