Many NBA coaches have done an exceptional job lifting their teams' performances to new heights this season, making this Coach of the Year race one of the tightest in recent history.

This season's contestants bring so much to the table that the coaches of the Western Conference's two best teams, the Houston Rockets' Mike D'Antoni and the Golden State Warriors' Steve Kerr, shouldn't even get much consideration. Each simply had "too good" a roster with which to work.

Comparing each team's performance with preseason expectations, while adjusting for injuries and in-season trades, here are my top five candidates and my No. 1 choice.

The contenders

Gregg Popovich | San Antonio Spurs

What would a COY race be without Popovich? Winner of three past awards, Popovich worked his magic once again this season.

With Kawhi Leonard playing only 210 minutes in nine games, Popovich has still managed to put the Spurs in position for home-court advantage in the very competitive West race. That's with reserve guard Patty Mills, "Slow-Mo" Kyle Anderson and 37-year-old Pau Gasol second, third and fourth in minutes, respectively. Bryn Forbes, undrafted less than two years ago, is playing about 20 minutes per game.

The Spurs will actually fall short of their projected 53 wins, but given they are missing a preseason MVP candidate, this performance is impressive.

Quin Snyder | Utah Jazz

The Jazz spent the majority of the season on the outside looking in. But with a 20-2 run starting in late January, they're almost certainly locked in on the West playoff chase.

If not for a fluke injury that knocked Ben Simmons out last season, Donovan Mitchell, the No. 13 pick of the 2017 draft, would be almost a lock for rookie of the year. And given he wasn't considered a star before the draft, he's emblematic of the kind of roster with which Snyder is working. Editor's Picks Lowe: These Raptors might be real and only getting better

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Rudy Gobert was the 27th pick and has never made an All-Star team, although he was the All-NBA second-team center last season and is surely a star when healthy. But he has missed 26 games this season. The other current players to start the season in Utah -- including Joe Ingles, Ricky Rubio, Derrick Favors, Jonas Jerebko -- don't look like the cornerstones of the West's third-best team by scoring margin.

Snyder's impact seems apparent, including the quick way he integrated the much-maligned Jae Crowder, who was added in a February trade from Cleveland. In fact, of all the five-man lineups with more than 150 minutes played, the Jazz's starting unit plus Crowder (and minus Favors) leads the league in plus-minus per possession -- quite the turnaround for Crowder, a longtime plus-minus star who sported one of the worst ratings leaguewide while with the Cavaliers.

The Jazz are projected to win 47 games, nine more than their Vegas preseason projections.

Terry Stotts | Portland Trail Blazers and Brad Stevens | Boston Celtics

Both Stevens and Stotts have coached their teams to surprising heights.

The Boston Celtics' hopes to contend seemed to collapse when Gordon Hayward suffered a gruesome ankle injury about five minutes into the season. Starting 0-2, they responded by winning 16 in a row, with Stevens the main constant in a season full of injuries.

Certainly two key figures have been Al Horford, playing some of the best basketball of his life at age 31, and Kyrie Irving, still a dazzling scorer and late-game highlight machine. But Horford and Irving have missed a combined 24 games.

What really has made this team crush its injury-adjusted projections has been the rapid rise of sophomore Jaylen Brown and rookie Jayson Tatum. The 21-year-old Brown has already developed into one of the league's premier wing defenders. Tatum led the NBA in 3-point accuracy for part of the season, and at 43.4 percent he still ranks ahead of Stephen Curry and Kevin Durant. Kudos to Stevens for taking an unpromising start to the season and putting the Celtics in position to finish a strong second in the East or even swipe the top spot.

Stotts, meanwhile, has led the Blazers to third place in the West, quite unexpectedly. In contrast to Stevens, though, Stotts has had a healthy team.

We could cite a bit of luck in both cases. When we look at expected wins, based on scoring margin, the Celtics have won five more games than expected, and the Blazers two. Of course, there are many reasons for winning close games, but the most consistent factor is good luck. Still, Stevens and Stotts have to rate near the top of the COY list.

My pick

Dwane Casey | Toronto Raptors

Vegas bookmakers had the Raptors pegged at 47 wins, a drop of four wins from last season. Some of that can be explained by expected regression to the mean. Additionally, the Raptors had played their best basketball in 2016-17 with Patrick Patterson on the court, outscoring opponents by 10 points per 100 possessions. Patterson went on to sign a contract with the Thunder that summer, making people wonder whether the Raptors could replace the impact of their sixth man.

Cut to eight months later, and the Raptors' bench is regularly mopping the floor with opponents. Patterson's plus-minus numbers -- now negative in Oklahoma -- aren't missed as every Raptors bench player (with more than 1,000 minutes) has an on-court rating of plus-8 or better. Fred VanVleet, another undrafted player from the 2016 draft, has even led the league for most of the season in plus-minus per possession and is now tied with Curry.

Yes, the Raptors' starting unit also outscores opponents by a healthy margin of around six points per 100 possessions. However, it's the bench that comes in and usually puts the game out of reach. But here's the best part: Aside from 30-year-old CJ Miles, the other four players of that bench group are either second- or third-year players. (Interestingly, they're not quite as young as you'd expect, as they played multiple years in college.)

What makes the Raptors' bench players so great? They do the little things well. Jakob Poeltl, the 22-year-old 7-footer from Austria, always prioritizes boxing his man out first before going for the rebound himself. And there's no opposing dunk attempt he's too scared to contest, which is part of the reason he's fifth in the league in blocks per 36 minutes.

And aside from Miles, who has never seen a shot he didn't like, everyone's willing to make the extra pass to find the open man. It helps that Delon Wright ranks in the top 40 in assist-to-turnover ratio -- Lowry ranks in the top 15 and VanVleet is in the top 10.

Pascal Siakam and OG Anunoby -- before Anunoby was promoted to a starting role -- hound opposing forwards with long arms and quickness. And yes, the 20-year-old Anunoby is starting for the team that sports a better point differential than the Golden State Warriors. Thanks to making 36 percent of his 150-plus 3-point attempts, he appears to be right on track to be one of the league's best future 3-and-D players.

When we run a multiyear age-adjusted RAPM analysis (real plus-minus' box-score-free cousin) of roughly 1,800 players since 2001, Poeltl and Siakam rank in the top 250 in terms of on-court impact, Wright ranks in the top 200, Anunoby in the top 110 and VanVleet in the top 70 (sandwiched between Dwyane Wade and Shane Battier). While we undoubtedly need to give credit to Raptors management for finding these players with the 20th pick or lower (except for Poeltl, who was picked at No. 9), the majority of the credit has to go to Casey and his staff for pushing all the right buttons, and ultimately creating the sixth-strongest bench since 1997 with an average age of just 25. On top of the stellar second unit, Casey also helped implement a revamped offense.

And that's why Casey would be my pick for Coach of the Year.