For a team trying to step forward, this misstep was significant.
Melvin Ingram, the team's pass-rushing outside linebacker and last year's first-round pick, tore his ACL in an OTA drill on Tuesday. It's not expected that he'll return for a season that was arriving with high expectations.
As the Chargers try to right their wobbly ship, Ingram was going to be among the defensive anchors. While he had but one sack last year, he was second among team linebackers with six quarterback hits and seemed to be on the fast track to a big second year.
But now head coach Mike McCoy's rookie year is going to include a defensive minus a proven pass rusher.
Not only is Ingram out, but the Chargers decided to let Shaun Phillips leave in free agency in the offseason. Antwan Barnes, another linebacker with a nose for the quarterback, also left as a free agent.
Ingram was to fill Phillips' spot, with a foundation of a decent rookie season catapulting him into a more productive role. But those plans ended Tuesday when Ingram came up on Philip Rivers during a drill. Ingram planted his left leg to stop, but it gave way on the team's natural grass practice field.
General manager Tom Telesco could turn to a familiar face in replacing Ingram.
Veteran Dwight Freeney visited the club after Ingram's injury. Freeney, an 11-year pro and a free agent, collected 107.5 sacks with the Colts, a span that coincided with Telesco's time with Indianapolis.
Freeney made the switch to a 3-4 alignment last year when the Colts went that direction in their base. He missed two games with an ankle sprain but still paced the team with 34 quarterback hurries and added five sacks.
The Chargers' options are limited on the roster. Larry English has been a first-round bust since 2009 with four career sacks. But he's in the last year of a contract and will be given every chance to stay on the field, if he can stay healthy.
The Chargers also drafted defensive end Tourek Williams in the sixth round and will convert him into an outside linebacker. Jarret Johnson is the other starting outside linebacker, but his forte his stopping the run.
Now the Chargers are scampering, trying to find someone to deliver a burst from the edge.