The NFL stands for not for long for a lot of players and teams. Whether as a Super Bowl contender or a bottom feeder, a team’s fortunes can flip in a season or less.

So far in the 2015 offseason, the two NFL teams in the Bay Area seem to be headed in opposite directions.

San Francisco 49ers

Let’s review.

Jim Harbaugh, who led the 49ers to three NFC Championship games and a Super Bowl appearance: gone.

Frank Gore, the franchise’s all-time leading rusher: headed to the Indianapolis Colts.

Patrick Willis, a seven-time Pro Bowler and future Hall of Famer in my mind: retired due to injury.

Justin Smith, a five-time Pro Bowler and defense leader: retired at 35 years old.

Chris Borland, who filled in for Willis last season and led the team in tackles as a rookie: retired due to concussion concerns.

That imposing defense that led the team to the Super Bowl a few seasons ago now has gaping holes to be filled. Of the 11 starters who took the field that game, only three remain with the team: defensive end Aldon Smith, known for getting sacks and getting arrested, linebackers NaVorro Bowman, coming off reconstructive knee surgery that sidelined him all of last season, and Ahmad Brooks, rumored to become a cap casualty this offseason.

To help fill these holes, the 49ers have signed players such as former Baltimore Ravens receiver Torrey Smith, a deep-ball threat who can hopefully help quarterback Colin Kaepernick improve from his drop in play last season.

Unfortunately it’s not 2013 anymore, and the combination of Anquan Boldin and Smith isn’t nearly as scary as when the Ravens beat the 49ers in the Super Bowl. And without Gore, the backfield —with the exception of Reggie Bush — is both young and unproven.

Oakland Raiders

Because of the league’s minimum spending rules, the Raiders were going to be big players in free agency. And while they may have missed out on some of the bigger names they wanted, the players they brought in seem to fit well and should help sophomore quarterback Derek Carr as he develops in his second season.

To keep Carr upright, the Raiders signed center Rodney Hudson, a former division rival, away from the Chiefs on a five-year, $44.5 million deal, making him the highest paid in his position in the NFL.

The running-back-by-committee approach looks to be continuing as the Raiders signed both Roy Helu Jr. and first-round bust Trent Richardson who join Taiwan Jones and Marcel Reece in a crowded backfield.

Helu, a Bay Area native, is expected to see plenty of action on third downs.

While the Raiders may have missed out on giving Carr a top-flight threat on the outside like Green Bay’s Randall Cobb or former Chicago Bear Brandon Marshall, the team is rumored to be targeting wide receivers Amari Cooper from Alabama and Kevin White of West Virginia in the upcoming draft.

Going Forward

As a 49ers fan it pains me to say it, but between Carr and the improving defense in Oakland, it wouldn’t surprise me if the Raiders finish this next season with a better record than the 49ers.

I can’t believe I just said that — the Raiders could be ahead of the 49ers by the end of next season. Yikes, has it really gotten that bad in San Francisco/Santa Clara?

Kevin Lucena can be reached at [email protected] or @klucena824 on Twitter