The San Francisco 49ers have endured a string of setbacks throughout the 2026 pre-season, and the latest blow is the news that veteran defensive lineman Aaron Donald is coming out of retirement to rejoin the Los Angeles Rams, a divisional rival the 49ers face twice a year. The timing is particularly awkward because head coach Kyle Shanahan admitted he does not yet know who will start at left guard when the team opens its season against Donald and the Rams, leaving a key defensive threat unmarked just days before kick-off.

The setback follows a run of bad news for the franchise: head coach Kyle Shanahan suffered broken bones, facial cuts and a concussion in a car crash in July after taking his eyes off the road; star pass-rusher Nick Bosa has not practised in four weeks while recovering from ACL surgery; tight end George Kittle has missed all of training camp following Achilles surgery; wide receiver Ricky Pearsall needed knee surgery in early August, likely ending his season before it began; and owner Jed York was arrested in a prostitution sting in Ohio, later pleading no contest to lesser charges. With the season opener against the Rams set for 10 September in Australia, the 49ers have traded for offensive lineman Jarrett Patterson for depth, but Shanahan says the left guard plan remains "truly fluid".