Handshakes and hugs might be just as prevalent as bone-jarring hits at Candlestick Park on Sunday.
"It's going to be quite a reunion," 49ers coach Jim Harbaugh said.
The Indianapolis Colts are in town with a slew of names familiar to Bay Area fans and close to Harbaugh's heart.
Atop the list is Colts quarterback Andrew Luck, who played for Harbaugh at Stanford and credits the 49ers coach for helping shape his career.
Luck also worked closely with 49ers offensive coordinator Greg Roman, who was Stanford's assistant head coach-offense, and he occasionally sought advice from Cardinal defensive coordinator Vic Fangio, who holds that position with the 49ers.
"It will be fun to see those guys," Luck said. "They taught me so much about football. But at the end of the day, it will be another game."
That's the prevailing sentiment of the 14 former Stanford players and coaches involved in Sunday's game.
The Colts' list includes offensive coordinator Pep Hamilton, tight end Coby Fleener, backup receiver Griff Whalen and reserve safety Delano Howell.
In addition to the brain trust, the 49ers have six players and coaches who were with Harbaugh at Stanford, including recently acquired fullback Owen Marecic and defensive assistant Peter Hansen, whose father, Earl Hansen, is the famed Palo Alto High coach and a Harbaugh mentor.
"We'll be adversaries, but it's not adversarial," Fleener said. "I always root for them to do well -- just not this week."
The visit overlaps with a Stanford home game, but team commitments will likely prevent Luck, Fleener, Whalen and Howell from watching their alma mater play Arizona State at 4 p.m. Saturday.
Fleener, a second-year tight end, caught four passes for 69 yards and a touchdown Sunday against the Miami Dolphins. He'll have an expanded role this Sunday in the wake of a season-ending injury to starter Dwayne Allen, one of several injuries that threaten to undermine the Colts' rebirth.
After their lost season of 2011 -- quarterback Peyton Manning was out with neck injury -- the Colts stunned the NFL last year by winning 11 games and reaching the playoffs without coach Chuck Pagano, who missed most of the season while undergoing treatment for leukemia. Luck set a handful of rookie passing records and lived up to his billing as the most NFL-ready quarterback to enter the league in years.
"He's unflappable; he's tough as nails; and when things break down, he can extend plays," Pagano said this week. "He wills the team to win."
When offensive coordinator Bruce Arians left last winter to become coach of the Arizona Cardinals, the Colts tapped into the Stanford pipeline again and hired Hamilton, who worked closely with Luck during his final college season.
Hamilton's connection to their franchise quarterback was a secondary consideration for the Colts, according to Pagano.
"We went out to find the best guy for the job," he added. "It so happened he worked with (Luck) at Stanford."
Hamilton's NFL roots run deep. He spent seven years in the league, including one with the 49ers, before joining Harbaugh staff at Stanford in 2010. Just as Harbaugh and Roman have taken the playbook used at Stanford and adjusted it to accommodate the 49ers' personnel, so has Hamilton in Indianapolis.
Like the 49ers, the Colts favor a punishing running game. Their midweek acquisition of Cleveland Browns running back Trent Richardson, the third pick in the 2012 draft (two spots after Luck), will help.
"The offenses are all based on same thing, but it's changed so many ways that each team has something unique," said Whalen, who has two catches this season.
"They're one of the top teams in the league. It's going to be a tough, physical game. But we're familiar with that smash-mouth mentality."
Between handshakes and hugs, they can reminisce about it with Harbaugh before the game.