Butler was touched on the right elbow by Marcus Smart on a turnaround jumper as the horn sounded, drawing a foul.
The Bulls' leading scorer stepped to the free-throw line and drilled both foul shots, making him nine-for-nine for the game and giving him 29 points.
"It was a big letdown", added Smart, who stripped Butler earlier in the final minute to keep the Celtics ahead at the time.
Covington left the game in the fourth quarter after hitting his head at or near the Boston bench diving for a loose ball.
Hearthstone Marks 2017 as the 'Year of the Mammoth'
Perhaps the biggest changes, though, are not found in the release schedule, but rather in the changes to the Standard game format. Most cards should feel like situational additions to a deck, depending on the deck archetype the player is trying to build.
In fact, coach Fred Hoiberg chalks up the recent up-and-down play to up-and-down health, which featured the Bulls not having Dwyane Wade for a third straight game.
Butler isolated against Marcus Smart on the left side of the court as the final seconds ticked off the clock.
Whether or not there was contact, it probably wasn't close enough to make that call. "We get up for the challenge", Gibson said. The Butler-Thomas matchup was terrific theatre down the stretch, as Thomas scored 11 fourth-quarter points on 3-of-8 shooting while Butler had a crucial block on him with 1:10 left.
Hundreds evacuated as bushfire rages in New Zealand city of Christchurch
The hills surrounding Early Valley Road on the Port Hills are left with the scars of a fire that raged for four days and nights. Civil Defence said it had confirmed 11 homes had been razed but added the situation was constantly changing.
Hoiberg, who has National Basketball Association experience as player, coach and in the front office, said before Thursday's game he does his best to ignore the rumor mill when it comes to the upcoming trade deadline. Smart has not only started to distinguish himself with improved point guard play but has helped fill the void left by Evan Turner's departure this summer.
"It's what he wants". One year later, the disenfranchised Rondo was traded away to Dallas and the Celtics haven't looked back. He's a guy that's going to go out and take the challenge, anything that is given to him.
Bulls: Host the Phoenix Suns next Friday night.
The C's have won 11 of 12 and sit just 2.5 games back of the Cleveland Cavaliers for the top spot in the Eastern Conference.
Weather: Temps dropping before warm afternoon
This Friday's outlook calls for sunny skies with a high of 41 before temps take a dive in the evening to the freezing mark. The forecast includes mostly sunny skies Friday and partly sunny skies Saturday , according to the weather service.
As for the Bulls, Hoiberg was pleased his team was able to enter the All-Star break with a pair of wins in hand. And barring a blockbuster deal that sends Butler to the team he tormented for 40 minutes on Thursday, the Bulls will have that player as they continue their push toward.500 and a postseason berth. Moving forward we can't worry about who we're beating.