After jumping out to an early 14-point lead, the San Francisco 49ers lost to the Los Angeles Chargers, 29-27. Niner Noise has your full position grades and analysis from the Niners’ Week 4 matchup.

Injuries, turnovers and mistakes played a major role in the San Francisco 49ers’ third loss of the season, as the team fell to the Los Angeles Chargers 29-27 in front of a Los Angeles stadium filled with Niner fans.

Sunday was a fitting ending to a month of season-ending injuries to key 49ers starters, including starting quarterback Jimmy Garoppolo and top running back Jerick McKinnon — as well as potential long-term injuries to important starters, including top cornerback Richard Sherman and strong safety Jaquiski Tartt.

Four of the 49ers’ five starting offensive linemen sustained injuries during the game, as did two of the Niners’ wide receivers, top wideout Marquise Goodwin and rookie WR Dante Pettis.

Injuries certainly played a role in the Niners’ squandering of an early two-touchdown lead, but San Francisco’s problems span beyond mere personnel issues caused by injuries to key starters.

Backup strong safety Antone Exum‘s interception-return touchdown was the 49ers’ play of the game, while the Chargers’ top play was 49ers tight end Garrett Celek not only dropping a key red-zone pass, but popping it into the air for an 86-yard interception return.

San Francisco’s defensive miscues included a plethora of missed tackles, as well as multiple mistakes in coverage; At one point, Los Angeles tight end Antonio Gates was covered by defensive lineman Solomon Thomas deep downfield, and on a key third down, Gates wasn’t covered at all for an easy touchdown score.

Each week, Niner Noise breaks down and grades the performance of each of the 49ers’ position groups. We’ll start with the San Francisco 49ers’ offense: