I've been thinking about this a lot lately, and the more I think about it the more I'm certain that JJ would ultimately be the best fit for us starting at the 4. Now, of course if we plan on keeping KO and want him to be the 4 next to Horford for us longer term, then that would certainly be a good argument for starting him as much as possible. However, I'm not necessarily considering that, and I'm just considering who would be the best fit at the 4 for us this year with this current group with IT, Bradley, Crowder, and Horford starting at the 1, 2, 3, and 5, respectively.

What are the main things we need from the 4 this year?
1) Rebounding
2) Floor-Spacing
3) Defensive Versatility (both ability to switch onto forwards/guards and a focus on perimeter D)

Rebounding: 1) Amir, 2) JJ, 3) KO

Amir is pretty clearly the best rebounder of the bunch. He was a pretty good rebounder for us last year, even next to Sully, and his ORB%, DRB%, and TRB% were 10.3, 19.6, and 14.9. His biggest advantage is in offensive rebounding, compared to JJ (6.8 ) and KO (5.4). However, JJ nearly equaled him in DRB% with 19.4 with KO farther behind at 16.2. This held in the playoffs, too, where Amir went 8.1, 26.6, and 16.8 compared to JJ's 4.2, 23.4, and 13.2. So Amir is the best rebounder of the group, and JJ is a little behind him with KO quite a ways behind him.

Floor-Spacing: 1) KO, 2) JJ, 3) Amir

Similar to above, the first two have quite a separation over the third guy. KO and JJ are excellent shooters, especially from the corners. For FG%, 3P%, and eFG%, KO went .455, .405, and .531 for the season. Not far behind, JJ went .413, .398, and .488 for the season. Amir had an excellent fg% at .585, but he was essentially not a three point threat at .233 only attempting one every two games, not to mention how long it took him to get off his shot. However, in the playoffs as a started JJ upped his game significantly. While his 3P% dropped a bit to .318, though we know he's still a major threat from beyond the arc, his FG%(.478) and eFG%(.554) improved quite a bit as the starter.

This is one of the most important roles that our starting PF will play this year, because it will finally give the C's some easy opportunities for points in the half court setting. Think about it - last year neither Amir nor Sully represented any significant floor-spacing threat, which killed the spacing for IT in his penetration. This year with either Horford/JJ or Horford/KO, every single player on the floor will be a pretty big threat from beyond the arc, creating massive space for IT's penetration. In the halfcourt setting this will be huge for us, because in Brad's pace and space offense, all we have to do is move 2-4 out beyond the arc to give IT all the necessary room to either penetrate and score or penetrate and kick if the defense collapses. This will finally be the easy, reliable offense that we've so desperately been missing in past years.

Defensive Versatility: 1) JJ, 2) Amir, 3) KO

This is another area where the top two provide significant distance from the third player. Both JJ and Amir are above average defenders, but they're better in differing areas. Amir is a much better rim-protector than JJ, as evidenced by his block numbers/percentages; however, JJ is the much better perimeter defender due to his athleticism and foot speed/lateral movement that Amir no longer has. Now, Amir is no slouch, but he was constantly falling down when switching onto smaller/faster players due to simply not having the lateral speed that he once had, especially out on the perimeter. When we think of a team like Cleveland, I'd much rather have JJ out there with his ability to switch onto James and Irving than Amir, and definitely not KO.

So how does all of this come together to make JJ the best fit for us starting at the 4? Well, it's clear that he provides the best two-way fit for this current group.

While Amir would provide better rebounding and rim protection, JJ provides better perimeter defense and defensive versatility than Amir, which we need more than rim protection at the 4 with Horford at the 5, and he is a only a marginally worse rebounder than Amir, especially on the defensive end. And while KO would provide better playmaking and marginally better shooting than JJ, Horford's presence and excellent playmaking from the big position makes playmaking at the 4 less of a concern, and JJ is only a marginally worse floor-spacing threat than KO.

One other advantage of starting JJ would be that you also strengthen the bench with the excellent pairing of KO and Amir together. A bench of Rozier, Green, Smart, Brown, KO, Amir, and Zeller is arguably the best in the league, and it legitimately allows Stevens to go 10-12 deep regularly in the season without too much drop in play.

Thus, while KO might be the better offensive player and Amir the better rebounder and rim-protecting big, JJ is the more solid overall player and the best fit next to Horford in the starting lineup that doesn't necessarily provide the big holes that KO (rebounding and defensive versatility) and Amir (floor-spacing) do.

Thoughts?