Washington Wizards' Otto Porter Jr. (22) shoots in the first quarter of an NBA basketball game against the Boston Celtics in Boston, Saturday, Dec. 21, 2013. (AP Photo/Michael Dwyer) I can’t come out here and watch. (AP Photo/Michael Dwyer)

BOSTON – To ease Otto Porter Jr. into the rotation, Coach Randy Wittman has given the rookie a chance to show what he can do during harmless stretches in the first half or midway in the third quarter; never at a time when the game could potentially slip away.

But that changed on Saturday afternoon in Boston, where Wittman called on Porter to replace Trevor Ariza with 11 minutes 23 seconds left in the fourth quarter with the Wizards trailing by four points. When Porter left the court about five minutes later, the deficit was just six – despite a torrent of buckets from Celtics guard Avery Bradley – and the Wizards were in position to stage a rally that resulted in a 106-99 comeback victory.

“We have to come off the bench and we have to produce, have to give our starters some time to rest and come back in to finish the game,” Porter said. ‘That was my main focus coming in, to try to do as much as I could to keep our team in it.”

Porter, the third overall pick last June, matched his season high with four points and brought the Wizards within 88-84 when he caught a pass from Garrett Temple and made a reverse layup. “Otto played really good,” Wittman said. “He’s getting his feet wet. He battled. I just want to see him continue with the effort, focus and belief, going out there and being Otto Porter.”

With Bradley Beal on a minutes limit because of his right leg injury, Wittman has had to find a way to be creative and not put too much pressure on Ariza and Martell Webster to carry the load. Porter didn’t play in New York and only got three minutes against Brooklyn, but he got 11 minutes against the Celtics after taking a more assertive approach in practice.

“I’ve seen improvement. I’ve seen confidence. I’ve seen him be more active,” Wittman said. “That was as active as he’s been and I can see in his face that he’s getting comfortable. Going out and playing and knowing what he has to do, hopefully he can keep that going.”

When Porter entered the game in the first quarter, he didn’t hesitate to pull up for a midrange jumper after rebounding an errant shot by Celtics center Jared Sullinger. He missed, but wasn’t deterred. Porter later hit a 19-foot jumper from the right side of the hoop early in the second quarter.

“That’s what Coach is telling me: continue to be aggressive, when you get out there, play, and get your confidence back,” said Porter, who is still regaining his form after missing three months with a strained right hip flexor.

Porter is in a tough spot to be an immediate contributor in Washington. Not only does he have to develop confidence in his body coming back from a serious injury, but he has to prove that he deserves to be in the rotation with two established players in Ariza and Webster playing the same position.

Because this is his first year, Porter is still learning on the fly without the benefit of a training camp or preseason.  And with the Wizards making a push for the playoffs, he doesn’t have the luxury of learning through his mistakes, as previous top selections John Wall and Beal. But his slow but steady progress could only help the Wizards become a deeper team going forward.

“I think it’s great for him, just getting into a comfort zone,” Wall said. “I think he’s still trying to find a rhythm and it’s good to see him out there competing, making shots and willing to make plays and put the ball on the floor. And one thing he does a great job of, is as a rebounder. That surprised me because I didn’t really see that. I think if he just keep playing and we keep encouraging and he’s getting better and doing better and playing every day in practice, all it’s going to do is change over into the game.”

The win over Boston gave Porter the first chance to go up against a fellow Georgetown alum in Jeff Green. Green spoke to Porter before the game, telling him, “I’m coming at you.”

Porter said, “I was like, ‘Okay.’ ”

Late in the second period, Porter got the chance to match up with Green after Ariza collected his third foul. Ariza had a hard time trying to keep Green in front of him. Green immediately called for the ball in the low post with the scrawny Porter on him, but Porter held his ground and forced Green into shooting an air ball.

“When he’s out there, when I’m playing against him, it feels a lot better, because I’m familiar with playing against Jeff,” Porter said. “It definitely was fun. I’m one for one, I guess [against fellow Hoyas]. It was great.”

The win in Boston was the first time that Porter scored in a Wizards victory. Not a bad way to enter the holiday season.

“No better way,” Porter said with a smile. “This is what we wanted. So, happy holidays.”