There are so many players outside the Los Angeles, New York, Miami and, yes, even Oklahoma City spotlights. I know it sounds implausible, but good players actually do exist elsewhere. The San Antonio Spurs actually used to be the go-to for unsung talents, but they've received something of a recent, widespread congratulations for nearly two decades of fine work.
I would reference this Bill Simmons column from the Spurs vs. Thunder series, an ode to San Antonio greatness that all but handed them a 2012 title. The point isn't to single Bill out. The Spurs were playing superlative basketball and his opinion reflected a broad consensus. I'm citing this as a means of demonstrating that, yes, even the "boring" Spurs have their supporters.
It would also be tempting to choose a player from among the aforementioned spotlighted NBA cities. Pau Gasol doesn't get his full due in Los Angeles, even after winning two titles and making three NBA Finals. Tyson Chandler might have won Defensive Player of the Year, but he couldn't get to the All-Star Game. James Harden is still coming off the bench, despite being a much better player than Thabo Sefalosha.
In Miami, Chris Bosh is as vital as he is made fun of. I would even say that Dwyane Wade is underrated, on account of having outplayed Dwight Howard over the past three years and not being considered the better player in most consensus rankings.
Instead, when searching for my "under-appreciated" player, I turn to the unloved Hawks. Atlanta opened the season with 50-to-1 odds for winning the East, despite Bradford Doolittle's projection of the Hawks as the second-best Eastern Conference team (via ESPN). Perhaps Vegas has different odds, but some of this is probably related to how little public money comes in on behalf of Atlanta.
The Hawks aren't a draw, though one of their players regularly appears in highlights. Perhaps you're familiar with the ever exciting, frustrating, rim-rattling, shot-swatting, jumper-shanking work of one Josh Smith.
Much as I'd love to put Josh in this spot, he is well-known for exciting play. Also, despite fine defense, he saps some of his value with terribly inefficient jump shooting.
Instead, I'm picking an Atlanta player who does well on both ends of the floor. One whose star can be dimmed by playing out of position on account of Josh Smith's presence. I'm talking about Al Horford, who might be recognized as one of the game's best power forwards were he allowed to play that position.
Atlanta is forced to play Horford at center, and he performs as capably as a 6' 8.75" center can. I believe he would make for a better power forward due to his sweet outside shooting. Horford was out last season with injury (another reason for why he might be somewhat forgotten), but the year before that, he hit an incredible 53 percent of shots between 16-23 feet (via Hoopdata).
The ability to nail the pick-and-pop jumper stretches a defense and makes life easier for guards in pick-and-roll. If a defense respects a big man's ability to shoot, then it must take some attention away from the guard handling the ball. Lanes open up, defenses break down.
In total, Horford has averaged a .537 field goal percentage and 18.1 PER over the course of his still-young career. A solid rebounder, Al has claimed a career average of 10.1 boards per contest. He's the rare big who can hit a long jumper and rebound ruggedly near the rim.
Not only does Horford provide value on offense and on the boards, but he moves well on defense—even in the rare instance of coming back from a season-long injury, right in the middle of the playoffs.
The main flaw in Al Horford's game is that he's made to play out of position, against larger players. Despite that hindrance, he still manages to be among the game's most underrated players based on production alone.