One day after asking our Celtics Summer Forecast panel to predict the biggest overachiever for the Boston Celtics during the 2016-17 season, we flipped the script and asked, who will be the Celtics' biggest underachiever?

Rookie Jaylen Brown, who tied with Gerald Green atop the the overachiever category, finds himself tied for the top spot in the underachiever category as well. Both Brown and fourth-year big man Kelly Olynyk received 22.2 percent of the vote, while Terry Rozier and Tyler Zeller were behind them at 11.1 percent apiece. Al Horford, Isaiah Thomas, Avery Bradley, Jordan Mickey, R.J. Hunter and James Young each showed up on one ballot (5.6 percent).

Brown's presence on both lists isn't totally unexpected. The No. 3 pick in June's draft, Brown is balancing the expectations of his draft position with the reality that he's a 19-year-old rookie on a team pegged to win 50-plus games and compete for a top spot in the Eastern Conference.

The challenge for Olynyk will be working his way back to being the player we saw in the first half of last season before the shoulder injury derailed his campaign. Olynyk had offseason surgery and is enduring what will be at least five months of rehab. The injury could sideline him for the start of the season and diminish expectations, but even summer splurge Horford name-checked Olynyk multiple times at his introductory press conference and seems genuinely excited to eventually play alongside the floor-stretching big man.

Al Horford's enormous contract will leave him open to charges of underachievement almost no matter how well his debut Celtics season goes. Brian Babineau/NBAE via Getty Images

Some readers will cry foul seeing Horford and Thomas on this list, particularly considering our panel recently voted the duo Boston's best bets for All-Star representatives. Alas, that's a reminder of how high expectations are for those players, and there's always the chance they could underperform.

Forced to make a selection, this writer might actually vote for Horford, if only because his mega-sized contract will lead to immediate and lofty expectations. No matter how seamlessly most expect Horford to integrate into Boston's system, there could be some small bumps, and we'll see exactly how he settles in offensively, when you consider that younger guys like Bradley, Thomas and Jae Crowder will all be trying to maintain their own production. This isn't necessarily to say that Horford will struggle, it's simply that his expectations might simply be higher than most on the team because his contract is so eye-popping compared to most of Boston's team-friendly deals signed before the latest spike in the cap.

A sample of our panel's responses:

Alex Kungu, CelticsBlog (Rozier): I think a little too much has been made from Rozier's summer-league performance, and it will lead to inflated expectations. Rozier will be improved, but he still won't be good enough to run an NBA offense and a lot of the ballhandling workload will still fall to Marcus Smart.

Bobby Manning, CelticsBlog (Brown): For a young player as raw as Brown, there's reason to expect he'll probably fall below expectations of the No. 3 overall pick. The rotation will be in flux, coach Brad Stevens will be searching for shooting internally again and even though there are fantastic tools at Brown's disposal, the immediate goals of the team could supersede his development. There's even a chance, however small, he'll spend time with Maine in the D-League to work on his overall game and get consistent reps. Stevens will give Brown every chance, especially early, as he always does. But the first view of him could disappoint some. He won't necessarily underachieve, but I could certainly see him contributing less than anticipated -- and that's no knock on a rookie, despite what Karl-Anthony Towns has set as a standard.

Jon Duke, "Celtics Stuff Live" on CLNS Radio (Brown): Underachievers are those who cannot meet expectations. Sometimes the efforts of underachievers are truly terrible, and in other instances it's unrealistic expectations which are to blame. I suspect Brown will improve and develop nicely as a player, but his strong finish to summer league have some thinking he can be a significant contributor immediately. I'd like to see how Brown responds to a team that has scouted his poor shooting, but my guess is his response will push him to the bench more than some expect.

Sam Packard, WEEI-FM 93.7 (Rozier): I think Rozier could be doomed by his dominance in summer league. Celtics fans are going to expect him to come in and be ready to run the second unit. I think he will show massive improvements from last season, but don't think he is ready to fill the facilitator role Evan Turner played last season.

Mike Dynon, Red's Army (Hunter): Assuming James Young isn't on the roster -- a possibility, with Boston carrying 18 contracts at the moment -- Hunter is next into the danger zone. I really hope I'm wrong, but Hunter shot just 36.7 percent last season. He must improve that or else he'll have trouble seeing the floor.

Justin Poulin, "Celtics Stuff Live" on CLNS Radio (Olynyk): I'm tempted to select Smart for biggest overachiever and underachiever for the same reason: Expectations are high as he is poised for a breakout year. Smart is in an impossible position, but I'm a believer that he will rise to the challenge. You could go with players such as Hunter, Young or Mickey, but they really shouldn't be in the regular rotation and the choice should come from the top 10 rotation players. Olynyk is quietly in a similar position to Smart. He is the best at what the Celtics need most (3-point shooting) but was not able to get in the gym through the summer after shoulder surgery. This could disrupt his performance. Rebounding will likely be a concern for the Celtics, too, and it might spell trouble for Olynyk if he's not shooting the lights out.

Ryan Bernardoni, CelticsHub (Horford): Who are the options? Most of the veteran players have modest salaries and pedigrees so they would have to be pretty bad to significantly underachieve. Maybe Olynyk and Smart are expected to step up a few levels and so could underachieve? I don't expect Horford to be bad, but as a 30-year-old making more than twice as much as the second-highest-paid Celtic (and at least three times as much as anybody after that), he simply has the highest starting expectation and so the most space to underachieve. It's possible that he could make the All-Star team, be the second or third-best player on the team, and still be the biggest underachiever.

Bill Sy, CelticsBlog (Brown): Top-three picks are expected to hit the ground running, but that burden shouldn't be put on Brown. He’ll certainly get his opportunities. Brown is already a plus defender and has shown an ability to drive and draw contact. But Brown is still very young at 19 years old. He’ll flash star qualities from time to time, but fans hoping Celtics general manager Danny Ainge selected an All-Star in waiting will have to be patient.

Dan Greenberg, Barstool Sports (Brown): Brown's the choice, only because of what the players taken in the two spots ahead of him will be doing during their rookie seasons. Both Ben Simmons and Brandon Ingram will have better numbers simply because of opportunity. Brown is walking into a completely different situation in Boston, so compared to those two rookies, we will probably say he underachieves.

Sean Penney, CelticsBlog (Olynyk): We keep waiting for Olynyk to break out and, as he heads into his fourth season in the league, we're still waiting. A 7-footer who can shoot better than 40 percent from beyond the 3-point arc has value, but the flashes of brilliance we've seen have been marred by injuries and inconsistency. He can still make an impact off the bench, but many expected more from him by now.

Sam Sheehan, Celtics Reddit and CLNS Radio (Thomas): Since I'm assuming James Young will be off the roster, I'm going to go with Thomas here. This isn't to say that I think Thomas will have a bad season, per se. I just think the Celtics will all play more or less the same, and Thomas played out of his mind last season; a regression to the mean is to be expected. While the addition of Horford will help with defenses keying on Thomas, I still think it's some lofty expectations to assume he's an All-Star again. I thought about Crowder as another possibility here, but at the end of the day, I'm going to pick Thomas as the guy who takes a small step back. I really hope I don't end up on his Twitter for this.

Lachlan Marr, CelticsBlog (Zeller): I like Zeller, and I don't think underachiever is exactly the right word here. He's generally consistent at what he does, but even when playing to his full potential he's not exactly a star player. It would be an overachievement if Zeller showed any development at all, really. But I think it's likely Zeller will continue to show exactly what we've seen so far, which would instead be considered an underachievement.

Rich Jensen, Red's Army (Olynyk): In terms of championships and playoff series, Olynyk is definitely good enough to win a game or even multiple games, but I don't think he has the durability or the strength to play opposite the other team's starting center night in and night out and still be a net positive for the team. And I have my doubts about Horford wanting to play center full-time as well. In fairness to Olynyk: I also didn't think Thomas would hold up playing starter's minutes the way he gets pounded, and he was an All-Star last season.

Tom Westerholm, MassLive (Zeller): I'm not sure I honestly expect any player to underachieve (since I suspect James Young will be gone before the first game). But Zeller could see an even bigger reduction in his minutes, and it can be tough to get a rhythm when your minutes are cut significantly.

Mark Van Deusen, CelticsLife (Mickey): How can a 22-year-old second-round draft pick be labeled an underachiever in his sophomore season? I think there's a large contingent of Celtics fans who legitimately expect Mickey to make an impact next season, and I just don't see how it can happen. He'll likely be in the 13-15 range on the team depth chart and will probably see more minutes in Maine than he does in Boston.

Ben Mark, Red's Army (Olynyk): There's so much positivity around this team, so it's hard to pick a guy who might underachieve. I chose Crowder last season and, well, that didn't go so well. I'll choose Olynyk, whom people seem to believe will be a deadly stretch-4 next to Horford this season. Olynyk has been really slow to bounce back from injury -- as evidenced by the original shoulder injury before the All-Star break last season. He'll have to come back from injury again to start this season, and I don't think it will be seamless.

Jared Weiss, CLNS Radio (Bradley): Can I still write Jared Sullinger? Bradley finds himself caught on the opposite end of a familiar situation. In 2012, he pushed Ray Allen out of his starting spot with his tenacious defense and newfound corner 3. Now Marcus Smart is knocking on that door. Bradley is currently surrounded by players with ball skills and could see his looks decrease. However, Smart would have to be able to reliably shoot off the dribble to threaten Bradley’s spot in the rotation. Bradley is still somehow just 25 and has steadily grown every year of his career, so his risk to underachieve only goes as far as Smart overachieves.