Then humility kicked in like the talented but still raw LSU defensive end had never experienced it before when the diagnosis or a torn ACL was delivered.
Encountering those two indignities didn't derail Montgomery's enthusiasm. He still talks about football like a kid who can't sleep on Christmas Eve.
But the injury, surgery and then the arduous rehabilitation to fight his way back have changed the 6-foot-4, 245-pound sophomore – for the better – both physically and mentally.
"It really humbled me," the gregarious Montgomery said last week in his first session with the media this season. "I came out last year I was a little cocky because I felt like I was ready to dominate. I had no idea how raw I still was. I just went out there and let my natural ability carry me in those first four games.
"When I got hurt, it humbled me and made me go back to the film and strategize more than I ever had before. It made me realize that technique is the key. You can have speed, power and be the greatest athlete ever, but if you're not disciplined and don't know the scheme as well as you have to, it can cost you."
Whether it's his love the cartoons he was devoted to as after-school entertainment through his senior year of high school or his story about meeting South Carolina coach Steve Spurrier for the first time and having no clue who The Ol' Ballcoach was, Montgomery will fill dead air for long stretches.
When it comes to talking about his rebuilt knee and what it took to climb back to where he feels comfortable enough to play at the same level – or better – stirs something up in Montgomery.
Something different and emotional. Happily emotional.
"It's just great to be back, great to be back out there," he said. "I still need to build up my stamina and still have a lot to learn, but I also think I'm better technique-wise than I've ever been.
"I'm just so glad to be back out there. It feels almost the same and maybe even a little stronger. I'm not worried about doing anything differently, or waiting on any kind of setbacks. I walk out of here with a smile on my face every day because I'm back on the field again."
LSU coach Les Miles isn't surprised Montgomery has taken the mental and emotional path he's travelling down. Injured players tend to choose one of two routes – wallowing in self-pity or using the down time to get better in any way possible.
Montgomery, it seems, is a poster child for the latter.
"With young guys, the one thing they take for granted is their bodies," Miles said. "You think you're invincible. You think you won't get hurt. You've always tested it and it's always showed that it's up to that challenge. Then when you have injury, it really works on you emotionally and certainly it did Sam."
"Sam wanted to play and he was having a great season, and suddenly it's over. It takes some time. He had to get his mind right academically because it was a distraction to him. Then he turned the corner and started rehabbing, and started realizing the path back was hard work, and he's used to hard work."
Fortunately, with a redshirt season in 2009 and a feisty spring leading into 2010, Montgomery has also gotten used to competition and fighting for a job.
Back to full health, Montgomery has stepped back into a spot on the first unit at right defensive end, but there's plenty of push coming from junior Lavar Edwards, sophomore Barkevious Mingo and the newest kid on the defensive end block, sophomore Jeremy Maclin.
With Montgomery on the shelf for the final eight games last fall, Edwards took over at right end and was effective with 21 tackles, 2½ sacks and an interception he yanked down and returned 29 yards for a touchdown. Mingo was even more of an impact player as a speed rusher in passing situations with 35 tackles, 2½ sacks, six pass breakups, four QB hurries and two forced fumbles.
Now that he's healthy and at full speed, Montgomery is a more complete package than Edwards or Mingo – a proven run-stopper on the edge who can also get upfield in a hurry to harass the quarterback or drop back in pass coverage against fullbacks and tight ends if needed.
If he's limited at all, though, Montgomery knows Edwards, Mingo and even Maclin are waiting in the wings for a chance to get on the field, even as part-time fill-ins to give him a break.
"We have so many people I have so much confidence in, I'm fine with coming off the field if it makes our defense better and gives us the best chance to win," said Montgomery, who recorded 18 tackles and two sacks last season in four games and a handful of snaps in the fifth contest.
"With me missing all that time last year, guys like Lavar and (Mingo) got a chance to show what they could do and Maclin moved in from linebacker and learned the position. It's important for all our guys to be able to play the run well, play the pass well and to jump back into coverage. We don't want anybody who can't do something in any situation at any given time."
While Edwards, Mingo and Maclin promise to provide nice depth behind Montgomery and starting left defensive end Ken Adams, there's no debate about how important it is to the defensive ends group to get Montgomery back.
Cut from similar cloth as former Tiger Kelvin Sheppard, Montgomery's leadership skills have made an immediate impact in pre-season camp.
"It's great having Sam back because he knows what to say to get us going," Mingo said. "He's a leader out there and we know now that he's healthy, he's going to play hard and set the tone for us that way, too."
And Montgomery emerging as a new leader couldn't happen at a better time for LSU's revamped but very talented defense.
The departure of Sheppard, tackles Drake Nevis and Pep Levingston and cornerback Patrick Peterson left four gaping holes on the Tigers' defense both production-wise and leadership-wise. So anybody willing and able to shoulder some responsibility on both fronts is welcome and immediately valuable.
"We lost a lot of guys who did the talking in the locker room and on the sidelines and especially in the huddle, so there are some big ol' shoes to fill," Montgomery said. "We have a lot of guys who need to grow up quick and I'm one of them.
"I can be a leader by talking, but I also need to go out there and reach my maximum potential. I'm back to 100 percent and ready to do that."
That sounds a lot like reality and humility swirled together, with plenty of confidence to tie it all together.