49ers’, Raiders’ free-agency approaches couldn’t be farther apart

Oakland has opened its overstuffed wallet to secure a road-grading offensive lineman (Kelechi Osemele), an elite edge rusher (Bruce Irvin) and a top cornerback (Sean Smith) for $43.9 million in guaranteed money.

In 2015, the Raiders took significant steps under first-year head coach Jack Del Rio and the rising-star trio of quarterback Derek Carr, rookie wide receiver Amari Cooper and linebacker Khalil Mack.

[...] the 49ers kept regressing under since-fired rookie head coach Jim Tomsula and disgruntled and demoted quarterback Colin Kaepernick.

Smith, who was being courted by the 49ers, chose to sign with the Raiders, and no observers argued with his logic.

[...] is there truth to the popular story line that the Raiders have become a destination and the 49ers are now a disaster?

[...] after back-to-back home-run drafts by general manager Reggie McKenzie and the hiring of Del Rio, whose leadership galvanized players last season, the Raiders are in a position to do so.

Maybe a bully offensive lineman, a pass rusher to complement Mack and their first true No. 1 cornerback since Nnamdi Asomugha left.

Osemele had back surgery in 2013 but played well last year, and the team thinks he can be an impact player at guard or tackle.

Irvin didn’t become the next Aldon Smith as the Seahawks had planned, but he has shown he can get to the quarterback and is a favorite of defensive coordinator Ken Norton Jr.

Oakland is one of four teams in on former Chargers Pro Bowl safety Eric Weddle, who plans to look at initial contract offers and take the weekend to consider where he visits first.

CEO Jed York noted the team’s salary-cap space ($53.7 million) and slew of draft picks as he expressed confidence in general manager Trent Baalke’s ability to rebuild.

The 49ers have committed at least $5 million annually to bring back their top in-house free agent, nose tackle Ian Williams, on a five-year deal.

Baalke no doubt rolled his eyes in recent days as other teams doled out mega money for marginal players.

The 49ers could be surveying the free-agent landscape and concluding that the best way to start rebuilding is by focusing on their 12 draft picks.

Last year, puzzled wide receiver Torrey Smith, who signed with the 49ers in 2015, said he never experienced leaks to the media during his first four seasons with the Ravens.

[...] free agents with options may also be leery of playing for a coach known for his devotion to sports science (daily urine tests) and frenetic-paced offense (running, running and running).

Five years later, however, the only NFL turnaround that looks imminent in the Bay Area involves the Raiders.