-- Editor's note: This story has been updated to reflect the news of Derrick Jones Jr.'s injury.
Do injuries to guards Lonzo Ball and Alex Caruso threaten the Chicago Bulls' surprisingly strong season?
Within days, the Bulls learned they'd be without both of their playmakers and defensive stalwarts due to injury. On Thursday, Ball underwent arthroscopic surgery to repair a meniscus tear in his left knee that the team said is expected to sideline him six to eight weeks.
Two days later, Chicago announced that Caruso will also need surgery after suffering a broken wrist when he was flagrantly fouled by Milwaukee Bucks guard Grayson Allen on Friday night. Caruso's timetable to return is also six to eight weeks.
Although overshadowed by the addition of DeMar DeRozan, the defense, shooting and playmaking provided by Ball and Caruso have also helped the Bulls go from the lottery to leading the Eastern Conference before Friday's loss. They join a lengthy injury list in Chicago that also includes All-Star guard Zach LaVine, who's currently sidelined by knee soreness but expected to return sooner, and starting power forward Patrick Williams.
With the East standings crowded at the top -- the Bulls are second, a half-game back of the Miami Heat, while five other teams are within 1.5 games of them in the standings -- Chicago's positioning is precarious.
Let's take a look at the implications of Ball and Caruso missing the next several weeks.
Expect a defensive slide for the Bulls
The most surprising aspect of Chicago's strong start was the team's stout defense. As recently as Christmas, the Bulls ranked in the league's top 10 in defensive rating, checking in ninth at 107.5 points allowed per 100 possessions, according to NBA Advanced Stats. The following day, Ball entered health and safety protocols, missing the next five games. Not long after his return, Caruso was also lost to the protocols. Caruso was sidelined until the game Wednesday night.
With limited minutes from Ball and Caruso, Chicago's defense has suffered. Since Dec. 26, the Bulls have allowed 113.9 points per 100 possessions, a mark that ranks 22nd in the NBA. Chicago has barely outscored opponents in that span despite a top-10 offensive rating, relying on clutch heroics from DeRozan to go 9-6.
Caruso has had an enormous impact. The Bulls defense allows 10.7 more points per 100 possessions with Caruso on the bench, according to NBA Advanced Stats, the third-largest differential among players with at least 600 minutes this season. However, Chicago's defense has truly collapsed with neither Ball nor Caruso on the court, as we saw during the first two games Ball missed. In 1,034 possessions without them, the Bulls' defensive rating ranks in the 5th percentile among all lineups leaguewide per Cleaning the Glass data.
Unlike a lot of defensive splits, this one doesn't owe to fluky opponent shooting. Instead, the problem is Chicago can't stop teams from getting to the hoop without either Ball or Caruso defending at the point of attack. Per Cleaning the Glass, nearly 40% of opponents' shot attempts have come around the rim in these minutes, a rate that ranks in the second percentile leaguewide.
We saw this effect each of the last two Bulls games. They outscored opponents by 20 points with Caruso on the court but were outscored by 11 with him on the bench.
Chicago's depth will be tested
Besides the specific value of Ball and Caruso, losing them for an extended stretch is also painful because the Bulls' injuries are mounting. They've played nearly all season without forward Patrick Williams, whose wrist surgery might sideline him the remainder of the schedule. Now a fourth Chicago player will be sidelined 6-8 weeks: forward Derrick Jones Jr., who suffered a right index finger fracture while already dealing with a knee hyperextension that had him out of the lineup.
The combination of injuries left Alfonzo McKinnie (who was initially signed to a hardship deal before inking a minimum contract that is now guaranteed for the rest of the season) and Tyler Cook (on a two-way contract) starting at power forward before Javonte Green returned for Monday's win in Oklahoma City. The Bulls also got All-Star guard Zach LaVine back for that game after the team went 1-4 in his absence.
Until a four-game losing streak that included lopsided losses to the Nets and Golden State Warriors at home, Chicago had been able to hold things together. The team won nine in a row after returning from an eight-day pause caused by a number of players entering health and safety protocols, and five of those wins came when Ball was unavailable.
It helped that Coby White was ready to ramp up his minutes just as Ball and Caruso missed time. While White isn't nearly the defender at the point of attack they are, he's scoring more efficiently than at any point during his first two seasons. White is making a career-high 37% of his 3-point attempts and shooting a career-best 53% inside the arc.
Additionally, the Bulls have gotten valuable contributions from second-round pick Ayo Dosunmu, another quality perimeter defender for Donovan to employ. Dosunmu dropped to the second round because of concerns about his offense translating, but he's played within his limitations and hit 44% of his limited 3-point attempts -- far better than his 34.5% career accuracy from the shorter NCAA line.
Still, at some point the Bulls' depth might be stretched too thin. Losing Ball and Caruso also makes Chicago a much smaller team. Their size as guards (Caruso is listed at 6-foot-5, Ball at 6-6) helped compensate for the Bulls' small frontcourt and allowed Donovan to use lineups with four perimeter players around center Nikola Vucevic.
Why every game counts for playoff seeding
Fortunately for the Bulls, Ball and Caruso (as well as Jones) should be back before the end of the regular season. Nonetheless, their injuries might be felt come playoff time in terms of where Chicago is seeded. The race for the six East teams who will advance directly to the first round if the season ended today is already tight and figures to remain so.
FiveThirtyEight's projections have Chicago tied for the fifth-best average record in the East at 46-36 with the Cleveland Cavaliers. The surging Boston Celtics are just a game back of that.
Despite how well the Bulls have played thus far, they're now in jeopardy of dropping to seventh in the East and needing to advance to the playoffs via the play-in tournament for the first time since trading Jimmy Butler in 2017. Even if the Bulls can avoid that, they are trending toward unlikely to maintain home-court advantage in the opening round.
With a healthy Ball and Caruso, Chicago could still be a tough out this spring. However, its path in the playoffs is likely to be much more difficult because of their injuries.