The Jets’ quarterback drama took another twist yesterday with David Garrard preparing to walk away from football, increasing the chance Mark Sanchez remains with the team.

Garrard plans on retiring, according to a source, but nothing has been made official yet.

According to another source, Garrard has been struggling with his left knee, which he had surgery on last year, during the team’s voluntary workouts over the last month. The source said Garrard has grown increasingly frustrated with it.

Garrard told SNY’s Adam Schein in a text message the knee was forcing him to walk away.

“Having to call it quits,” Garrard said. “My knee is not holding up. Continuing to swell after practices. Limiting what I can do.”

The move throws the Jets’ quarterback situation into total disarray. Garrard was thought to have a good chance to start the season and mentor rookie Geno Smith. That would have allowed the team to part ways with Sanchez. Now, it looks like Sanchez will stick around for another season.

The Jets signed Garrard in March to compete with Sanchez, knowing Garrard was an injury risk. Garrard has not played since 2010, missing the 2011 season with a back injury and last year with the knee problem that flared up during training camp with the Dolphins.

The hope had been Garrard would compete with Sanchez and Smith throughout the summer. Instead, they now are down to a competition between Sanchez and Smith with Greg McElroy getting a better chance to stick around as the third quarterback. Matt Simms also remains on the roster.

The Jets cut Tim Tebow last month after drafting Smith, leaving five quarterbacks on the roster. There is no chance the Jets would bring him back.