SANTA CLARA, CALIF., Jan. 18 -- The San Francisco 49ers know the value of their backup quarterback, Steve Young, probably the best No. 2 man in the NFL. They know he is capable of starting for most teams. The 49ers know they could get a number of draft picks or players should they wish to trade him. They know all of this and they simply don't care.

Because the 49ers feel they can win with Young when their star, quarterback Joe Montana, can't play or is weakened, as he is now. The team announced yesterday that Montana is sick with the flu he caught from his family last week and is listed as probable for Sunday's NFC championship game against the New York Giants at Candlestick Park. But don't look for Montana to miss the game.

Should Montana for some extraordinary reason not be able to play or is ineffective -- the 49ers said yesterday was the first day of practice Montana missed this week -- they are confident in Young.

"What he gives us," Coach George Seifert said, "is a quarterback we can win with should something happen to Joe."

In a strange way Young is almost as valuable to this team as any of its star players. He is one of the most respected and liked players by his immediate peers. His skills as a runner and passer are well known throughout the league: Of the nine games Young has started with the 49ers, they have won seven of them.

"I think you're always aware of the fact that Young could come in the game and present a different style," said Washington Redskins defensive coordinator Larry Peccatiello. "I don't think you could develop two separate game plans for a player, you just don't have the time to do that.

"I think Young has very good athletic talent. He is more apt to scramble and is quicker than Montana. When he gets out of the pocket, he's dangerous. In that regard he reminds me of {Philadelphia Eagles quarterback} Randall Cunningham. And let me say this: I think Young could present a challenge to some quarterbacks in the league for the starting job."

When Montana goes down because of an injury, Young steps in, scrambles, zig-zags, sometimes lines up as a wide receiver, throws deep, and little is lost.

"Joe is one of the greatest quarterbacks I've ever seen and he does things that few quarterbacks can do," safety Ronnie Lott said. "And I think that Steve has a chance to be a great one in his own right. We know that if Joe should for some reason go down, we can win with Steve."

The contract that made Young the fifth highest paid player on the team expires at the end of the season, and all interested parties say Young likely will be back. For his part, when asked if he will leave the 49ers, Young said this is the system he would like to play in and he wants to make the Pro Bowl as a 49er. While Young acknowledges he could start for plenty of teams, he would rather bide his time with San Francisco. Young won't discuss the possibility of him leaving any more than that.

"I know what I can do," Young said. "I'll just leave it at that."

Young (Brigham Young), a Heisman Trophy runner-up in 1983 to the Falcons' Mike Rozier (Nebraska), has only thrown 109 passes in his four seasons with the 49ers. But it is how Young has done when he has played that makes people wonder what would happen if he is given the chance to be a consistent starter.

There was one game this season in which Young showed what he's capable of doing. He replaced injured Montana and played the second half of San Francisco's final regular season game against the Minnesota Vikings. Young finished 15 of 24 for 205 yards and two touchdowns.

"That was a big win for the entire team not just me," Young said. "Of course I like getting the opportunity to play like that. I wouldn't be a very good competitor if I didn't."

His value is being proven again this week. Because the 49ers' defense practices daily against Young, he has helped it prepare for another scrambling quarterback in the Giants' Jeff Hostetler.

Hostetler rushed for 43 yards last week against the Chicago Bears, including two runs of nine yards on fourth down. The 49ers are worried about the rushing ability of the Giants' quarterback and Young gives San Francisco's defense a sneak peak at what Hostetler is likely to do.

"There's an unknown factor because we ourselves haven't played {Hostetler} a whole lot," Seifert said. "We don't really know him, yes, but we have played guys like him. Guys like him are maybe a {John} Elway or Steve Young in practice."

"What I try to do is make the defense worry about me, if I'm going to run or throw it," Young said. " . . . Usually you give them a couple of pump fakes to keep them thinking."

Thinking is what Young will be doing when the season is over. He must decide if he wants to be the NFL's most talented backup or go elswhere and try to become one of its most talented starters.