The San Francisco 49ers knew this day was coming — the day when one of the league’s most talented rosters would command a total salary far in excess of the NFL’s limit.

So they are prepared to move forward — even if it means leaving several mainstays behind.

The 49ers enter the free-agent period staring at the possibility of losing their leading rusher, their second-leading receiver, a Pro Bowl guard and two of their top three defensive backs. Don’t be surprised if they don’t blink.

After all:

–They used a second-round pick on running back Carlos Hyde last year. He appears more than capable of replacing an aging, yet still productive, Frank Gore.

–They have their highest draft pick in years — No. 15 overall — in a deep pool of wide receivers, which could easily offset the loss of Michael Crabtree.

–They in essence offered injured guard Brandon Thomas, a third-round pick last year, a redshirt season in 2014, grooming him for Mike Iupati’s starting spot as soon as his surgically repaired knee permitted.

–And they’ve spent their last two first-round picks on members of the secondary (safety Eric Reid and defensive back Jimmie Ward), giving themselves options to play along with standouts Tramaine Brock and Antoine Bethea should corners Chris Culliver and Perrish Cox walk.

Is it possible Gore, Crabtree, Iupati, Culliver and Cox will all play elsewhere in 2015? Absolutely. Adding to that possibility is the fact the club chose not to use its franchise tag on any of the quintet, paving the way for all to seek greener pastures.

With very little money to spend in free agency and other holes to fill — namely, defensive end and third wideout — the 49ers should be expected to be far more a seller than a buyer in this year’s market.