By his admission, Green Bay Packers coach Mike McCarthy has planned for next season with one number in mind: 579.

As every Packers fan knows, that is the eye-popping yardage total rung up by San Francisco as it ushered Green Bay out of the playoffs in January. Averaging 7.7 yards per play, the 49ers dropped a 45-31 wake-up call on the Packers.

But as McCarthy and general manager Ted Thompson begin to assemble their next roster, starting with this week’s NFL draft, they would be wise to consider another number: 51.

As every Packers fan should know, that is the number of times quarterback Aaron Rodgers was sacked last season. Although Rodgers is the face of the franchise and, probably very soon, its wealthiest employee, he suffered more abuse from opposing defenses than any quarterback in the NFL last season.

The Packers’ playoff disappointments the last two seasons revealed more weaknesses than anyone suspected, but as Thompson and McCarthy contemplate using their first-round draft pick — No. 26 overall — Thursday night, their top priority should be to give Rodgers better protection.

Though the line isn’t entirely at fault, the protection for Rodgers has fallen far short of the protection Brett Favre received late in his Packers career. During his five seasons as the starter, Rodgers has played in 86 games (regular-season and playoffs) and been sacked 223 times. In his final five seasons in Green Bay, Favre played 85 games and was sacked only 95 times.

At 29 and in his prime, Rodgers’ importance to the Packers is immeasurable. And when he signs a contract extension that will make him the highest-paid player in the game, the Packers will need to do more than protect their quarterback. They’ll need to protect their investment.

For that reason alone, the Packers should lean toward taking the best offensive lineman that falls to them at 26. Green Bay needs to rev up its running game and upgrade its pass protection to take the pressure off of Rodgers, and using one or two premium draft picks on linemen would be the quickest, safest way to get that done.

It won’t be easy for Thompson, whose draft-and-develop philosophy is predicated on taking the best available player. Plus, there are other needs to address. San Francisco’s offensive explosion showed the defense could still use work and the Packers’ long-standing need for a franchise running back remains an issue.

However, it all starts up front, and the Packers must get bigger and more physical to match up with NFC powers San Francisco, Seattle and the New York Giants. McCarthy said recently the line needs to improve on the left side, from the center on out.

In the playoffs, the Packers lined up with two undrafted players — right tackle Don Barclay and center Evan Dietrich-Smith — and three mid-round picks in left tackle Marshall Newhouse and guards Josh Sitton and T.J. Lang.