The San Francisco 49ers arrived in Australia hoping to acclimate early and eliminate as many variables as possible before their historic season opener.
Instead, they lost a starting defensive lineman before playing a single snap.
Alfred Collins will miss the entire 2026 season after tearing the patellar tendon in his knee during Tuesday’s practice in Melbourne, head coach Kyle Shanahan confirmed Wednesday. The injury occurred only days before San Francisco faces the Los Angeles Rams at the Melbourne Cricket Ground.
For a defensive line already dealing with injuries and uncertainty, the timing could hardly be worse.
What Happened to Alfred Collins?
Collins suffered the injury during San Francisco’s second practice in Melbourne. Shanahan confirmed the diagnosis Wednesday and described the loss as another significant challenge for a position group that had already lost defensive end Sam Okuayinonu to a broken foot.
There is no uncertainty about Collins’ immediate status.
His second NFL season is over before it begins.
Collins had been listed as the first-string right defensive tackle on San Francisco’s unofficial depth chart, opposite veteran Osa Odighizuwa. C.J. West backed up Odighizuwa, while rookie Gracen Halton and James Thompson Jr. were listed behind Collins.
The 49ers must now make that contingency plan real.
Why Collins Was Important to San Francisco
The 49ers selected Collins with the 43rd overall pick in the 2025 NFL Draft after he developed into a second-team All-American at Texas. At approximately 6-foot-5 and 332 pounds, he brought uncommon size and athleticism to the interior of San Francisco’s defensive line.
He appeared in 16 games as a rookie and entered Year 2 positioned to take on a much larger role. His value was not limited to sack production. Collins offered the size to occupy blockers, disrupt interior running lanes and allow San Francisco’s linebackers to pursue the ball without constantly fighting through offensive linemen.
That type of work does not always dominate highlight packages.
It does affect how an entire front functions.
With Collins unavailable, the 49ers lose one of their largest interior defenders and a young player they expected to develop alongside Odighizuwa.
C.J. West or Gracen Halton Could Start
Shanahan identified C.J. West and Gracen Halton as the two leading candidates to start next to Odighizuwa against Los Angeles.
West offers a little more professional experience. The second-year defensive lineman is listed at 6-foot-1 and 316 pounds and spent his rookie season developing inside San Francisco’s rotation.
Halton is the more recent investment. San Francisco selected the former Oklahoma defensive tackle with the 107th overall pick in the fourth round of the 2026 draft.
Neither entered the week expecting to handle Collins’ projected workload.
Now one may start in the NFL’s first regular-season game in Australia, against an offense that finished 2025 as the league’s best unit.
That is a significant first assignment.
The Rams Should Test the Middle Immediately
Los Angeles has every reason to make San Francisco’s replacement rotation prove itself.
The Rams can attack with Kyren Williams and Blake Corum, giving Sean McVay two capable runners with different styles. The pair combined for 129 rushing yards when Los Angeles defeated San Francisco 42-26 during their final 2025 meeting, with Williams scoring twice.
Expect the Rams to test the interior early with inside zone concepts, split-flow action and runs designed to force West or Halton to maintain gap discipline.
That does not mean Los Angeles will abandon Matthew Stafford or its passing game. It means the run game can become the mechanism that determines how much freedom Stafford receives.
If San Francisco’s replacements hold up, the 49ers can remain balanced defensively.
If they do not, the Rams can stay ahead of the chains, control possession and use play action against linebackers stepping aggressively toward the run.
Collins’ absence therefore does not affect only the defensive tackle position.
It could influence the way San Francisco calls the entire game.
The Injuries Are Beginning to Accumulate
Losing Collins would be difficult under any circumstances.
Losing him after Okuayinonu’s injury makes the problem considerably larger.
Okuayinonu started 12 games last season and recorded 39 tackles and three sacks. His ability to play multiple positions gave San Francisco flexibility across the front. The broken foot he suffered before the team traveled to Australia required surgery and is expected to keep him out for a substantial portion of the season.
The 49ers are also managing Nick Bosa’s return from an ACL injury, while Mykel Williams begins the season on the reserve/PUP list. That leaves a unit expected to generate pressure increasingly dependent on younger and less proven players.
San Francisco still has elite defenders elsewhere.
Bosa remains a premier edge rusher when healthy.
Fred Warner gives the defense one of football’s best linebackers.
Odighizuwa provides veteran stability inside.
But the margin has narrowed dramatically.
More Pressure Falls on Nick Bosa
Bosa was already going to be one of San Francisco’s most important players in Melbourne.
Now the defense may need even more from him.
Interior disruption prevents quarterbacks from comfortably stepping forward when edge pressure arrives. Without Collins, the 49ers must demonstrate that West, Halton and Odighizuwa can still compress the pocket and prevent Stafford from escaping pressure simply by moving toward the middle.
If San Francisco cannot create that push, Bosa may win outside without finishing plays.
There is also the workload question.
Bosa is returning from a serious knee injury and should not be expected to solve every problem during his first game back. The 49ers need production from him, but they also need to manage a season that extends far beyond one opener.
That balance became harder when Collins went down.
This Is a Season-Long Loss
The immediate focus is understandably on the Rams.
The broader consequence lasts all year.
San Francisco constructed its defensive line with Collins occupying a meaningful starting role. Losing him after final roster cuts means most external replacements are already signed elsewhere, familiar with different systems or available for a reason.
The 49ers can elevate a practice-squad player, sign a veteran or explore the trade market. None of those moves instantly replaces a second-round pick who spent the previous year developing inside their system.
West and Halton will receive opportunities sooner than anticipated.
That could accelerate their development.
It could also expose San Francisco if either is not ready.
This injury does not eliminate the 49ers from contention.
It does change the defense’s margin for error.
Collins was not yet a star, but he was supposed to become a stabilizing presence inside. San Francisco could place him between proven defenders, allow him to absorb difficult assignments and gradually expand his role.
That plan is gone.
The 49ers now need West or Halton to become dependable immediately. They need Odighizuwa to provide consistency. They need Bosa’s return to generate genuine pressure rather than merely symbolic optimism.
Most of all, they need to survive the opening weeks without allowing one injury to create several additional problems.
The Rams will provide the first test.
Los Angeles has an experienced quarterback, a deep backfield and an offensive coach capable of identifying weak points quickly. If San Francisco’s new interior rotation is not prepared, McVay will find out before the first quarter ends.
Alfred Collins’ injury is not simply the loss of one starter. It forces the 49ers to reconstruct a critical part of their defense on another continent, one day before facing one of the NFL’s most dangerous offenses.
That is a difficult way to begin any season.
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