I felt like writing about two things today: How much I miss Amir Johnson being in the Toronto Raptors’ lineup, and how disappointed I’ve been with the Raptors’ play of late, despite the fact that they’ve won four straight, seven of eight and nine of 12, with shorthanded wins against Houston and Indiana in that span. Turns out, Johnon’s absence and the team playing below standards are related.

Now, I fully realize that complaining about a team’s play during a winning stretch – especially at the tail end of one of the franchise’s best regular seasons ever – may seem overreactive. It’s the basketball version of First World Problems or some other offensive hashtag trending to shame us all for whining about generally meaningless problems. Still, there are concering signs right now, and with the focus changing from appreciating the season that’s been to how it can become the postseason that was, it’s worth worrying about.

We’ll focus on the last nine games, in particular, narrowing in on the last four games. Prior to this nine-game stretch, the Raptors had a solid win against the Hawks, a double-overtime loss to the Thunder, and a mediocre three-game stretch against the Suns, Hawks and Pelicans. The four-game stretch also leaves out the Miami loss and focuses only on wins. That is, this isn’t a cutoff selected simply to highlight a point, because the team wasn’t exactly peaking to that point (they weren’t struggling either, but they’re also not struggling now).

Have a look at how the performance has changed:

Raptors Since Dec. 8, All Games Last Nine Last Four
Record 40-20 7-2 4-0
O-Rating 107.1 109.8 114.7
D-Rating 102 107.2 106.3
Net Rating 5.1 2.7 8.4
Home/Road 30/30 5/4 1/3
Strength of Opp. 0.48 0.41 0.44

While the wins have still been coming, the nine-game stretch shows they’ve been far less impressive, with the team’s victory margins shrinking against a relatively weak stretch of schedule. The offense has still been humming, which is impressive considering that Kyle Lowry missed time and Indiana was on the slate.

But the defense, woof. They gave up 103 points to a Rockets team without Dwight Howard and Patrick Beverley and mostly without Terrence Jones, gave up 94 to a struggling Pacers offense, and then gave up 98 and 114 to the league’s two worst teams, Milwaukee and Philadelphia, respectively. Pace plays a part in there, sure, but the team’s defensive rating – which accounts for pace – has dropped from a top-eight mark overall to a bottom-five mark over the last nine games. And again, look at the strength of schedule in that time, and keep in mind that it’s likely inflated given the realities facing Houston and Indiana when the Raptors matched up with them.

Part of this struggle could simply be late-season malaise. The team is assured of a playoff spot, they’re fairly likely to have home-court advantage, and their top players have endured quite a workload. It’s completely possible they’ve noticed the incredibly easy stretch to end the season – once looked at as a possible advantage – and taken their foot off the gas. That wouldn’t be an issue if this were, say, Miami, who have shown an ability to “flip the switch” when necessary. But the risk right now is that the Raptors could be entering the postseason playing somewhere below their best basketball.

But they’ve also played some of these games without Kyle Lowry and Amir Johnson, two of their three best players, maybe even their two best players, full stop. Lowry has gotten plenty of love for how well he’s played this year, and deservedly so, but it seems as if Johnson has once again slid into being underrated, at least by some.

He’s averaging a career-high 10.7 points on 56.2 percent shooting, which is obviously great, but many have pointed to how banged-up he’s looked at times (which is why I’ve suggested over and over the team give him as much time to rest his ankle as necessary). His rebounding and shot-blocking rates are down, his player efficnecy rating is only slightly above-average, and the emergence of Patrick Patterson has led some to broach the idea that maybe 2-Pat should be starting at the four (Tyler Hansbrough started over Johnson for four games earlier in the season, too).

Not to further my reputation as an unabashed Amir apologist, but don’t let that last paragraph fool you: he has been very good, banged up or not, and continues to be one of the team’s most important pieces. The role he plays is not one that stands out with conventional numbers, as most are surely aware by now – setting some of the best screens in the NBA, providing help defense, the ability to switch out onto guards in the pick-and-roll or handle the opposing team’s best non-guard, these are all immensely valuable but generally immeasurable.

There are some numbers that can help show his impact, though they can get complicated or messy. To wit:

*Of all Raptors lineups that have played at least 10 minutes together, Johnson appears in four of the top five in terms of net rating. If that time constraint is upped to 20 minutes, Johnson appears in three of the top five and six of the top eight.

*When Johnson is on the floor, the Raptors outscore opponents by 4.3 points per 100 possessions (PPC), compared to 2.8 when he’s off the floor. That continues a trend that’s been apparent for Johnson’s entire career, as his teams have performed 2.6 PPC better with him on the floor.

*Using ESPN’s new Real Plus-Minus statistic (don’t be scared, the math is difficult but it matches up fairly well with conventional wisdom/the eye-test), Johnson has been the league’s 12th most valuable player per possession this season, adding 4.84 PPC over a replacement player. The fact that he’s played slightly fewer minutes than other top names pushes him all the way down to 17th in total value, showing him as worth 9.19 wins over a replacement player.

*Like with on/off-court numbers, this extends back years – Regularized Adjusted Plus-Minus (RAPM) over 14 years shows that Johnson has been the league’s eighth-best player since 2001 in terms of impact on his teams, ranking 79th in offensive impact and 13th in defensive impact, improving his teams by 5.8 PPC (over 40,722 possessions, which is pretty crazy, though if you think that’s a lot, consider that Dirk Nowitzki has played 143,773 possessions in that time).

I get that numbers aren’t everyone’s thing, and some will just snark in the comments at nerds loving Johnson and why that doesn’t match up with real life. That’s fine, you’re welcome to do that.

But it’s also not really a surprise, if you’ve been watching, that the Raptors are surrendering 32.8 looks a game in the restrcited area over the past four outings (Johnson played just three minutes in that stretch), compared to 26.3 before Johnson went down. The teams they played in those games? They rank first, fourth, 20th and 27th in restricted area shots, so it’s not just a case of sample bias. Opponents shoot just 47.8 percent at the rim when Johnson is guarding them, per NBA.com/stats, 19th best among qualified players, the same mark Howard allows.

There’s a great volume of evidence building that shows that Johnson is one of the most valuable assets in the NBA. Just because he’s not the traditional scoring four that some want, or a beast on the glass, doesn’t mean he’s not very, very good. Many Raptor fans already know an embrace this, others don’t.

Johnson’s return isn’t, on its own, enough to make me think the recent blip on the defensive end will just disappear, but he’s a really important part of what the team does on that end for about 30 minutes a night, and he’s definitely going to help a great deal. He allows guards to be more aggressive with their primary coverage, gives Dwane Casey more freedom in determining who and when to switch on pick-and-rolls, and, by being the primary rim protector, can lessen the defensive load on Jonas Valanciunas (which is suddenly important given how well he’s played offensively).

The team has to hope he returns at 100 percent, and that his presence helps push the defense back to being firmly a top-10 unit with Johnson as the anchor. Even at less than 100 percent, though, as he’s been for most of the year, Johnson brings immense value.