Crowder fell awkwardly to the floor after a fast-break layup in the third quarter of Friday's loss to the Houston Rockets. The team initially expressed optimism that it was a minor injury, but Stevens said testing on Saturday confirmed a high ankle sprain that will keep Crowder sidelined as Boston enters a tough stretch of its schedule.
"After I talked to [reporters on Friday], [Crowder] went back in and saw the doctor and had developed a little bit of swelling, has a high ankle sprain," Stevens said. "He's going to be out a couple of weeks minimum."
The Celtics, thin at the swingman position, will be challenged to fill Crowder's role. Boston ended Sunday's practice with Marcus Smart and Jonas Jerebko wearing starter green, which suggests that both received reps with the team's first unit.
Stevens wouldn't reveal whom the Celtics are likely to start in Crowder's place -- backup swingman Evan Turner is another candidate -- but admitted they will have to get creative without Crowder.
"We'll decide [the starting lineup] on Tuesday morning after another 36 hours of thinking about it," Stevens said.
"[Crowder is] one of our most versatile players, certainly in his ability to guard. I think that a lot of perimeter players have perimeter defensive versatility, but there aren't a ton of guys that can guard 4s for long stretches or sometimes 5s for long stretches, and Jae can do all that. So that's one of the things that's going to be quite a balancing act without him, and we're going to have to have guys step up and play. We'll probably end up playing a little more traditional because of that, and we'll see."
The Celtics have often gone small this season, using three- and four-guard lineups with the likes of Smart at forward positions. Without Crowder -- and with Kelly Olynyk nearing a return from a shoulder injury that has sidelined him for the past 11 games -- the team could be forced to lean heavier on its big-man depth.
Crowder has started all 66 games for the Celtics this season. He's averaging career bests of 14.4 points, 5.1 rebounds, 1.9 assists and 1.8 steals over 31.9 minutes per game. The Celtics own a net rating of plus-5.3 points per 100 possessions when Crowder is on the floor. Most notably, the team's offensive rating drops 6.6 points without him, a notable drop-off that accentuates the recent uptick in offensive consistency from Boston's first unit as a whole.
Turner thinks the young guys can help fill the void in Crowder's absence.
"[Losing Crowder is] definitely tough," Turner said. "In general, Jae's playing so great. He plays the bulk of the minutes for us, and defensively and the versatility that we have with him on the floor, it's definitely tough. So the biggest thing is just getting him healthy. We've got a lot of capable guys, guys that have stayed ready throughout this process. So they'll have an opportunity to play.
"I think [the young guys will] probably be ready. They've been on ice. [Young] has been on ice for like two years. Terry had a great game the other night. R.J.'s definitely capable. So I think in the NBA, at the end of the day, it's just playing basketball. And I think they'll be fine. It looked like they had a great day of practice today and it will be great for them."
Said Stevens: "I think it's a heck of a challenge when you look at our week ahead, right? With George, Durant and DeRozan -- bang, bang, bang. But that's this league. That's why long, athletic, versatile guys are in such demand in this league. Again, we may be a little bit smaller at times at the 3 and we may be bigger than we've been at times at the 4. We'll see how it all plays itself out and pans out. We've got a lot of good players. It's a great opportunity for them, and it's a great opportunity for some of our younger players maybe to take a more pivotal role than they have so far."