Like any coach praising a player's upside, new 49ers defensive coordinator Jim O'Neil stood at the media podium and commended rookie defensive lineman Ronald Blair's ability "to find the soft shoulder" in an opposing line's game.
Wait, the soft shoulder? That's football jargon, and when asked to decode it, O'Neil energetically mimicked the demeanor of an offensive linemen getting bull rushed.
That's the type of instruction and passion a youth-laden 49ers defense will need to get them through this season. There will be growing pains, and there will be a massive workload as a byproduct of coach Chip Kelly's fast-break offense.
"When he's in front of the room teaching, you can definitely see he's stern, but he has that energy we need," safety Antoine Bethea said. "Even on the field, he's smiling, he's running around, he's talking trash. Pretty sure our defense can feed off that as well."
O'Neil, 37, replaces Eric Mangini, who a year ago replaced Vic Fangio, the no-nonsense wizard who directed the 49ers' dominant defenses from 2011-14.
"Jimmy O runs a bunch of complex stuff," quarterback Blaine Gabbert said. "So, it keeps us on our toes (in practice)."
What the 49ers defense lacks in star power is what O'Neil's aggressive schemes -- and increasingly versatile players -- must make up for this season.
"We've got a lot of young guys that are going to continue to develop as the season goes on," O'Neil said. "If a guy that starts out on the second string Week 1, but Week 5 he makes a big jump and he's better than the guy that started the year as a starter, that's the guy we're going to go with."
Week 5 is when O'Neil might get back one of his best players: outside linebacker Aaron Lynch, who must serve a four-game suspension for violating the NFL's substance-abuse policy.
O'Neil's game plans will vary from week to week. Cornerbacks will flips sides, to match their speed and size to opposing wide receivers. The super-sized defensive line will rotate to stay fresh. The linebackers will roam as they see fit -- and wherever NaVorro Bowman can build off last year's NFL-leading tackle totals.
Safety Eric Reid sees improvement in the O'Neil regime. "I know exactly what I'm doing and exactly what the guy next to me is doing," Reid said. "When you feel that way, you can be confident about the way you break on the ball."
Not everything goes as planned, however, and O'Neil experienced his share of that as the Cleveland Browns defensive coordinator the past two seasons. O'Neil previously coached Buffalo Bills linebackers (2013) and New York Jets defensive backs (2009-12) upon leaving the college ranks.
Injuries derailed the Browns' defense last season, and they allowed the fourth-most points. Coach Mike Pettine subsequently lost his job, and O'Neil found his next employer in the 49ers, but only after Kelly first offered the job to Houston Texans linebackers coach Mike Vrabel.
Regardless of who their coordinator is, the 49ers defenders are bracing for a lot of action, as was the case with the Eagles defenses in Kelly's prior three seasons.
"It's our job to embrace it," Bowman said. "I've never met a defensive guy that didn't want to be on the field. That's more plays, more tackles, so it's going to work out."