The San Francisco 49ers have spent the better part of the last two seasons watching injuries chip away at what should have been championship-caliber rosters, so Thursday’s news that Mike Evans would sit out practice with Achilles soreness landed with a heavier thud than a typical midweek injury report usually would.

Kyle Shanahan described the issue as nothing more than soreness, which is the same understated language the organization tends to use for most ailments, but any time the word “Achilles” gets attached to a 33-year-old receiver, the conversation inside the building and across the fanbase changes in a hurry.

What makes the situation more complicated is that the Achilles is not the only thing Evans is managing.

He has been playing through a painful rib injury he suffered against Arizona in Week 3, and rather than sitting, he gutted out the following two games and produced 12 catches for 189 yards and a touchdown, including his first 100-yard performance in a 49ers uniform against Seattle last weekend.

That kind of toughness is exactly why San Francisco brought him in this offseason, but it is also the kind of toughness that can push a veteran body past the point where soreness costs him months rather than days.

The rough summer Evans endured only adds to the concern. He missed significant chunks of training camp with a quad strain and then a groin issue, and while he battled his way onto the field for the opener in Melbourne, he has rarely been fully healthy at any point since arriving from Tampa Bay.

Players who are compensating for one injury often end up creating another, and an Achilles that starts barking while a receiver is protecting his ribs is the kind of chain reaction that trainers lose sleep over.

The 49ers also know better than anyone what an Achilles tear can do to an offense, having spent months waiting on George Kittle to work his way back from the one he suffered in last January’s playoff win over Philadelphia.

With Ricky Pearsall already lost for the season, Deebo Samuel facing a possible trip to injured reserve with a hamstring problem, and Christian Kirk only now beginning his return from a calf injury, Brock Purdy cannot afford to see his most reliable outside target disappear for the rest of the year.

San Francisco hosts Washington on Monday night, and the extra days give Evans some breathing room, but with a bye week approaching shortly after, the team has a real opportunity to shut him down and give his body nearly three full weeks to settle.

Losing Evans for one primetime matchup would sting, yet losing him in December, when the NFC West and playoff seeding are on the line, would be far more damaging.

Shanahan has preached caution with Evans since August, and this is the moment to prove he meant it.