Chris Herrington spells out my point as well.
Douglas is a replacement-level journeyman — more Keyon Dooling than Mario Chalmers or Beno Udrih in the annals of Grizzlies in-season back-up point guard acquisitions -- and he’s shot like it, making only 37 percent from the floor and 18 percent from three in 16 appearances with the Grizzlies.
A recent team talking point about the Grizzlies record when Douglas plays (10-2 at the time, now 12-5) is more correlation than causation (same with the team’s 7-2 record with Andrew Harrison as a starter when Mike Conley missed extended time), but the team has, on average, been good with him on the floor so far. Some of that is because the team has been great so far when Douglas and Conley have been paired. The Grizzlies were also good in far more minutes with Conley and Harrison together. Giving Conley more ball-handling help and allowing him to focus more on scoring was a rationale for both the Parsons signing and, to a lesser extend, the Baldwin pick. The team has gotten next to nothing from those players this season, but this line of thinking is likely to influence the team’s roster-management strategies again next summer.
On that same note here is a quote from Fizdale
It’s more about fit now and who plays the best together, and what gives my best players the best chance to be great,” Fizdale said. “Right now, every game is so critical when you’re fighting for home court (in the playoffs). So those are tough decisions coaches have to make. But I’m going to continue to evaluate over the next week or so.”
As already shown playing Conley alongside another ball-handler(Carter, Douglas, or Harrison) is how you maximize his skills. Just like playing Gasol alongside another strong defender(JaM or Wright) maximizes his offensive abilities as well.