As previously stated, Ty is now using only 3 players on the wing (although we're only 3 games into the 3-man wing rotation). Ty's trying to keep players' roles fairly consistent/simple (that is, he's not going to play Marvin at a big slot and a wing slot). The 3 players who make the most sense in those 3 slots are Gordo, Alec and RJ. They're all going to get minutes. In those 3 games, Gordo is averaging 36 minutes, RJ is averaging 33 minutes and Alec is averaging 27 minutes. I'd like RJ's and Alec's minutes to be flipped (while still bringing Alec off the bench).
PER is a terrible measure for players being used almost exclusively as off-ball players. RJ's job is to knock down open 3s and defend. He's shooting 42% from 3 this season. His defense has been bad (IMO), although he does provide a little extra size, allowing Gordo to slide to the 2, where he's a much better defender (this may be the biggest reason Alec doesn't get more of RJ's minutes: Even with the bulk he added this offseason, Gordo isn't that great defending physical wings one-on-one). Dude competes pretty consistently, and (arguably) provides veteran leadership/composure as well.
It's probably also worth pointing out that RJ is 4th in minutes per game, averaging about the same minutes as Alec so far. Given his role, his performance within that role, and the dearth of other options to fill that role (especially considering both Gordo and Alec are better defending the 2), it makes sense that RJ is getting minutes. Alec has done a pretty damn good job on catch-and-shoot jumpers though, which is absolutely HUGE if he's going to play with Trey and Gordo, so maybe he'll get more minutes as the season progresses.