HOUSTON — General manager Trent Baalke expects the NFL to announce any discipline for 49ers linebacker Aldon Smith before Saturday at 1 p.m., at which time their 53-man roster must be set.

Smith would not count against that roster if he’s suspended for the start of the season, freeing up a spot for another player.

Smith met with NFL commissioner Roger Goodell three weeks ago, and while the league has not announced any discipline yet for the 49ers’ sack artist, Goodell may have tipped his hand a bit Thursday.

In Goodell’s letter to NFL owners outlining the league’s strengthened stance on domestic violence and sexual assault, he also wrote about other infractions involving weapons offenses and drunken driving. Earlier this summer, Smith pleaded no contest to three counts of illegal weapons possession and two counts of drunken driving.

From Goodell’s letter:

“In addition to focusing on domestic violence and sexual assault, we will continue to maintain strong policies regarding weapons offenses. We are similarly working to strengthen our response to impaired driving.

“We have sought — unsuccessfully — for several years to obtain the NFLPA’s agreement to more stringent discipline for DUI, including mandatory deactivation for the game immediately following an arrest and a minimum two-game suspension for a first violation of law. We will continue to press our position on this issue in the hope of securing the union’s agreement.”

Reading into that, Smith would face at least a two-game suspension for his Sept. 20 drunken driving arrest. Goodell, however, is also expected to factor in Smith’s five-game absence last season when he voluntarily checked into a substance-abuse treatment center.

The 49ers are in Houston for the exhibition finale Thursday against the Texans.

Last month, Smith was sentenced by a Santa Clara County judge to 11 days on a sheriff’s work crew, three years probation and 235 hours of community service.

Most suspensions for personal-conduct violations have ranged between one and eight games since Goodell became commissioner in 2006. Prior to Smith’s ruling, Goodell recently drew widespread criticism for suspending Baltimore Ravens running back Ray Rice only two games after a domestic-violence incident.

In Goodell’s letter to owners Thursday, he apologized for not taking a harsher stance with Rice:

“We allowed our standards to fall below where they should be and lost an important opportunity to emphasize our strong stance on a critical issue and the effective programs we have in place. My disciplinary decision led the public to question our sincerity, our commitment, and whether we understood the toll that domestic violence inflicts on so many families. I take responsibility both for the decision and for ensuring that our actions in the future properly reflect our values. I didn’t get it right. Simply put, we have to do better. And we will.”

Goodell then stated that players will face a six-game suspension the first time they violate the Personal Conduct Policy regarding assault, battery, domestic violence or sexual assault that involve physical force, “with consideration given to mitigating factors, as well as a longer suspension when circumstances warrant.”

“Among the circumstances that would merit a more severe penalty would be a prior incident before joining the NFL, or violence involving a weapon, choking, repeated striking, or when the act is committed against a pregnant woman or in the presence of a child. A second offense will result in banishment from the NFL; while an individual may petition for reinstatement after one year, there will be no presumption or assurance that the petition will be granted. These disciplinary standards will apply to all NFL personnel.”

Will Goodell’s new, hard-line stance impact Smith’s upcoming discipline?

Smith, at least, will have the NFL Players Association to help make sure he’s treated fairly. In response to Goodell’s letter, the NFLPA issued a statement that read in part: “As we do in all disciplinary matters, if we believe that players’ due process rights are infringed upon during the course of discipline, we will assert and defend our members’ rights.”

For more on the 49ers, see Cam Inman’s Hot Read blog at blogs.mercurynews.com/49ers. Follow him on Twitter at twitter.com/CamInman.