Maria Taylor takes a look back at Jim Harbaugh's first three seasons in Ann Arbor as he gets set for the 2018 season. (0:58)

If you know Jim Harbaugh, you also know grinning isn't really the Michigan coach's go-to facial expression as game time approaches. A quick Getty Images search reveals a conga line of angry in-game screaming, a lot of incredulous open-mouthed WTH's, and side-eye glances up to the scoreboard, analyzing his team's in-game status. That's the kind of collection that has been compiled after three years of losing to Ohio State, Michigan State and bowl opponents.

These days, though, as the practice sessions count down to the Wolverines' season-opening trip to Notre Dame, Captain Comeback's smile is indeed ... coming back. That will happen when a man feels like he might have finally found that last elusive piece of the puzzle at the bottom of the box.

"People like him, you know? People want to be around him and want to play for him. They're confident in him."

AP Photo/Tony Ding

That quote isn't from someone talking about Harbaugh. That's Harbaugh talking about someone. A 6-foot-2, rocket-armed someone who arrived in Ann Arbor over the winter, former Ole Miss quarterback Shea Patterson. Harbaugh made the comment in a revealing, football-tossing interview with Marty Smith that will run during College GameDay this Saturday (9 a.m. ET, ESPN). And yes, he said it with a smile on his face. Suppressed, yes, but a smile nonetheless.

"There's so many things about a quarterback, that a quarterback impresses you with," Harbaugh said about the transfer who threw for 2,259 yards and 17 touchdowns for the Rebels last season. "You know, demeanor. He's cool. He's kind of got that winning 'it' factor. He's a really good thrower and also extremely athletic and smart. He's one of the guys, too. He's not an egotistical guy. He's for the team."

Those who have been around Harbaugh over the years know that look he wears as he talks about Patterson. The one that tells you he feels like he might have something truly special to unleash upon the world. I have seen it twice. One was in 2009, his third season on The Farm, while Stanford was playing at Wake Forest. Most of us were there to see running back Toby Gerhart. But during pregame warm-ups, Harbaugh couldn't stop grinning as he casually commented about the kid QB who was about to make his second collegiate start. His name was Andrew Luck. Even after the Cardinal lost, the coach was smiling about what he'd seen from the redshirt freshman. One year later, Luck and Harbaugh were celebrating together on the field at the Orange Bowl, having finished the season 11-1, ranked fourth in the nation.

But the first time I saw the Harbaugh Grin was in summer 1998 at, of all places, Dover International Speedway. The just-traded Baltimore Ravens quarterback was also co-owner of Panther Racing, a solid but typically second-tier IndyCar team. Before the race, dressed in his bright yellow Pennzoil firesuit, he grabbed me by the arm and said, "We're gonna win today." I politely smiled. They totally weren't going to win. A few hours later, in Victory Lane, he pointed at me through the confetti. "Told you." Again, the pregame grin had been justified.

So will his 2018 preseason grin receive a similar payoff?

This is Year 4 of the Harbaugh era in Ann Arbor. That perpetually most crucial of all seasons for any head coach, when the roster is fully his and the systems that his recruits sign on to complement should be fully in place. Harbaugh has climbed trees, slept on couches, met the Pope and walked the beaches of Normandy to build this roster. He's worked out in Florida, ripped off his shirt, held camps around the world and even tweeted at Judge Judy and Big Sean to build this roster.

It's a roster that has produced a punishing defense and a ground-pounding running game. This year's captains, seniors Tyree Kinnel (safety) and Karan Higdon (running back) and juniors Devin Bush (linebacker) and Ben Bredeson (offensive line), are a testament to what Harbaugh has built. But his efforts have yet to produce an elite quarterback. There have been elite quarterback moments that were punctuated by misfires and far too many turnovers. Michigan finished 2017 minus-4 in turnover margin.

In a college football world that seems to move faster and add more dimension with each passing season, the Wolverines' offense has looked like an old black-and-white newsreel.

There is nothing monochrome about Patterson's game, though. Over the past week, his teammates have thrown out descriptions of "swagger," "exciting," "versatile" and "dynamic." All due respect to Wilton Speight and John O'Korn, but that wasn't them. Certainly not on a consistent basis.

Jim Harbaugh and Andrew Luck led Stanford to an 11-1 record and Orange Bowl victory in 2010. Harry How/Getty Images

"In the time I've been here, he's been the hardest quarterback I've had to play against, practice-wise, because he does a lot," Kinnel said last week. "The play's never over with him. We're guarding receivers for a long time, because he's making plays in the backfield. He's a good thrower on the run, so he's definitely a guy. He's smart with his decisions, as well."

That includes the decision to try to pull a legend's jersey number off the retirement wall.

Patterson wanted to wear No. 2 at Michigan, but Charles Woodson put it out of commission two decades ago, with only a couple of exceptions. So Patterson made a phone call. "I got [Woodson's] information from Michigan to see if it was OK to wear his number," Patterson said. "He said, 'You can't wear it.'"

After realizing Woodson was joking, Patterson eagerly listened to what the Heisman Trophy winner said next: "He said, 'If you're going to wear it, just know what you're wearing it for. You've got to be a leader and show the guys how hard you work. Wear it with pride.'"

Of late, pride has been hard to come by -- certainly when it comes to the measuring stick by which all Wolverines are ultimately judged. The one that doesn't come out until the season's second half, when the Spartans, Buckeyes and bowl games reemerge on the calendar.

Few believe that Harbaugh's job is in danger, even if his 2-7 record in those games worsens this fall. Or if another first weekend of December comes and goes without any Maize and Blue on the sideline in Indianapolis for the Big Ten title game. But most everyone believes that here, on the eve of that crucial fourth year, the Harbaugh era is standing squarely at a State Street-like crossroads, its time of ultimate judgment having finally arrived.

That includes the man in the khakis, suppressed smile and all.

"[The criticism] is fair because we haven't won [big games]," Harbaugh told Smith last week. "So, you know, I think with anybody, you pour your heart and soul into something and you do the best job you can. And there's always going to be a hundred people, at least, who are going to tell you how you could have done it better."