Korver will be replaced in the starting lineup by Rodney Hood whenever Hood's sore lower back feels well enough to play. Hood went through shootaround Tuesday but was ruled out of the game.
"I just felt like it," Lue said when asked about the timing of his decision to bench Smith.
Korver scored 22 points, going 5-of-6 from 3-point range, and Smith had 14 points in 22 minutes off the bench to help the Cavs win 129-107.
Lue said afterwards that Korver's performance might make him reconsider the plan to start Hood right away, seeing as Hood will be on a minute restriction when he does return.
It is the second time this season that Lue has demoted Smith from the starting five to the second unit, also making the move to start the 2017-18 campaign, when Dwyane Wade was still on the team.
Lue said that Smith played "pretty good" off the bench against the Suns and detailed what he expect from Smith going forward.
"I think he's a guy that can catch and shoot, obviously, maybe put the ball on the floor at times," Lue said. "Make plays, make plays for himself, so we'll see how it works out."
Despite Smith averaging just 8.3 points on 39 percent shooting overall and 36.2 percent from the 3 line, Lue stood by the 14-year veteran, telling reporters last month that Smith earned that faith, in part, because of his role in helping the Cavs capture the 2016 NBA championship.
Since then, however, the 32-year-old Smith was suspended for one game for throwing a bowl of soup at assistant coach Damon Jones.?Smith is coming off a 1 for 7 shooting night in a loss to the Los Angeles Lakers on Sunday, scoring just three points in 23 minutes.
Lue said that he and Smith had a positive talk about the lineup change.
"It was good," Lue said.
Smith said that there was no conversation with his coach about the move.
"We didn't talk," Smith told ESPN. "He sent me a text [Monday], and I told him, 'No problem.' I didn't know that it was a 'talk.'"
Smith acknowledged he was surprised by the change.
"That's all right, though," Smith said. "I'm not upset about it. I just wish there would have been more dialogue, I guess."
When asked what his role will be now, Smith said, "Honestly, I don't know. I don't know."
"But I think it's good for the first unit though," he added, "because we actually get to have someone out there we're going to run stuff for and who is a threat, as opposed to having somebody who is not an option."
Smith said his scoring in the starting lineup came more in the flow of the offense, rather than featured sets.
"Those are 'go-get-'em' buckets," Smith said. "Those wasn't like, 'All right, look, this is what we're looking for …'"
He said with no featured sets, it can still lead to a night like he had against the? LA Clippers?on Friday, when he had 15 points on 6 for 15 shooting. Then he added, "It can go like that or it can go like the Laker game."
Smith didn't know if the change was a direct reaction to his poor night against the Lakers.
"My performance has been steady — it has not been great, it's been a lot of bad shooting nights — so it's been a pretty steady pace," Smith said.
When asked again about the timing of the change, Lue was tight-lipped.
"I decided to do it today," Lue said. "Next question."
Korver, who will turn 37 this weekend, made his second start with the Cavs since being acquired last season.
"It went all right, I guess," Korver said. "I have no idea what's going on. I don't know if this is a one-game thing. I really have no idea. I told Ty I'm ready to do whatever he needs, just tell me before the game starts. So tonight, I think with Rodney still out, just trying a couple new things but I'm not making much of it."
Hood is averaging 10.2 points on 41.1 percent shooting from the floor and 32.5 percent shooting from 3 in 11 games with the Cavs (four starts). He averaged 16.8 points on 42.5 percent shooting overall and 38.9 percent from 3 in 39 games with the Utah Jazz this season before being traded to Cleveland.