It's really not fair.

Still growing into the position, still learning the technique and timing of the offense, still a disquieting question mark in the eyes of many fans and media, Marshall Newhouse begins his first season as the opening-day starter at left tackle on Sunday.

And who will be there to welcome him? None other than the most fearsome, ferocious and formidable right-sided pass rush in the league: right end Justin Smith and right outside linebacker Aldon Smith (unrelated) of the San Francisco 49ers, who will be frothing at the mouth and licking their chops at the prospect of facing the inexperienced and unproven Newhouse in the season opener.

The two Smiths wreaked havoc, racking up a combined 21.5 sacks and five forced fumbles in 2011. They tore up most left tackles and guards. But against the 23-year-old Newhouse, a former fifth-round pick who started 13 games last season filling in for injured veteran Chad Clifton, it could get downright ugly.

One expert, FOX analyst and former NFL defensive lineman Tim Ryan, predicted just that. Ryan told the San Francisco Chronicle: “[Justin Smith will] destroy him. He’ll destroy him. … That’s a matchup that 100 percent favors Justin. He’ll play him right down the middle in terms of head up … and he’ll kill him in the run game. [Newhouse] will never move him off the ball.”

According to numbers compiled by the Milwaukee Journal Sentinel, Newhouse allowed a team-high 10.5 sacks last year, the most by a Green Bay lineman since 1990. He also led the team in pressures allowed – a statistic that includes all sacks, knockdowns and hurries – with 41.5. Many times, he looked utterly overmatched. But in some games, he held his own and even dominated, showing the natural athleticism that compelled the Packers to let go of decade-long starter Chad Clifton, a pillar of the offensive line, in the offseason.

In talking to the media on Friday, coach Mike McCarthy acknowledged the tall task in front of Newhouse and left guard T.J. Lang.

“Marshall is going against a premier pass rusher and the kind of guy who brings a lot of juice to their defense,” McCarthy said. “Justin Smith over there, the (stunt) they have is probably the best we’ve seen in quite some time, the way they execute it starting with Justin as the penetrator. T.J. and Marshall will both be challenged.”

And, as if remembering that the 49ers’ opposite defensive side includes end Ray McDonald (5.5 sacks in 2011) and outside linebacker Ahmad Brooks (seven), McCarthy added that the Packers’ entire protection unit will be tested.

“Marshall has a big challenge, really our whole offensive line," he said. "It starts up there for [San Francisco] on both sides of the ball, frankly.”

Right tackle Bryan Bulaga praised Newhouse’s progress, improvement and comfort level along the line. “Marshall will be fine,” Bulaga said. “He just needs to play his game, be on the same page as T.J. and just work well.

“Help is always built in, but there are going to be plenty of times when it’ll be man-on-man blocking and we have to do our jobs,” Bulaga said. “More than anything, it's going to be man-on blocking. We just have to take care of business. That's all part of the challenge."

Follow Packers reporter James Carlton on Twitter: @CBSSportsNFLGB and @jimmycarlton88.