I think it's because Brad has moved to using Morris in the starting lineup instead of Baynes/Theis.
That has shifted Al to the 5 instead of the 4. I think Al is more confident offensively taking shots from the 4 and also, Morris is more of a consumer of shots than Baynes.
Personally, I wish Brad would go back to starting Baynes and bring Morris off the bench. We've been horrible defensively with Morris in the starting lineup (over 116 points per 100 allowed) and the increase in offense has not come close to making up for it (107.3 points per 100 scored).
Sample size is way too small to be meaningful, though. Morris is a solid defender, as he showed against Charlotte. With our offense as stagnant as it is, Morris provides needed help with spacing. I think the level of skill on our team has influenced the desire to win the battle between starting units rather than managing/chipping into leads via the second unit.
But it isn't the offense of the _starters_ that is stagnant. It has consistently been the _bench_ (until Rozier erupted the last two games) that has laid an egg offensively.
If you believe Morris helps the offensive spacing and playmaking, it is more needed with the 2nd unit than with the starters.
And while the sample sizes are small (we are only a 1/4 way through the season, they are starting to have some weight and the differences in results (between Baynes starting vs Morris starting) are pretty stark. The samples will have to swing wildly in the opposite direction over the next 20 games to neutralize that huge gap.
The problem with starting Morris is that it forces Horford to play the 5 for more of the game when he's clearly dominating when he's at the 4 more often.