NBA.com's John Schuhmann is in Texas, following the Boston Celtics as they travel through the Texas Triangle.

SAN ANTONIO, March 17, 2008 -- It has been less than two weeks since the Celtics signed Sam Cassell. He has yet to take part in a full practice with his new team. But you wouldn't know it by how he came up big in the Celtics' 93-91 comeback win over the Spurs Monday.

Integrating any player into any system is not easy, especially when you don't have the time to teach him how the system works. Cassell has gone over the plays with his coaches individually and he has had shootarounds to get some work in. Some progress has been made, but Cassell really only knows two plays.

"He's getting better," Celtics coach Doc Rivers said before Monday's game in San Antonio. "Today at shootaround, he looked like he was getting more comfortable with sets. But it'll probably take all the way up to the playoffs [to get him fully integrated]."

Asked if he was comfortable with throwing Cassell into the rotation this early, River's response was honest. "I'm not comfortable with it, but I'm gonna do it." Because before Monday, there were just 17 games remaining on the schedule. And if Cassell wasn't thrown into the fire now, the learning curve would extend into the postseason.

But it's not like Sam Cassell doesn't know how to play ball. The guy has been in this league for 14 years. Only three active players have more experience. He may only know two plays, but Cassell doesn't always need plays.

Just give him the ball and let him back a smaller guard like Jacque Vaughn down and hit a short turnaround. Or just give him a screen up high to give him space and let him pull up for a jumper. That's exactly what helped the Celtics get back into the game in the second quarter.

When Cassell first checked into the game with 3:36 to go in the first, his team was down 11. By early in the second, they were down 22, and it was an 18-point game when the 38-year old took over. He scored 12 points in less than six minutes, helping Boston cut the lead to 10 at halftime. He made Rivers comfortable enough to leave him in the entire second quarter.

"We needed a spark," Cassell said. "I just do what I do, make a shot here, make a shot there, just trying to allow my team to get that momentum."

He came back in to start the fourth and had a miss and a turnover early in the period. But don't worry about Sam Cassell. He never lacks confidence, and he'll make shots when the game is on the line.

With the Celtics down seven and less than four minutes to go in the game, Paul Pierce drove and found Cassell open for a long two to keep it close. And with less than a minute to go and Boston down one, another Pierce drive created (via Kevin Garnett) an open three for Cassell from the left wing. Cassell didn't hesitate, knocking down the jumper to give his team the lead for good.

In just his fourth game with his new team, he had hit the game-winner against the defending champs in their building.

"Late in the game," Pierce said, "that's what he does. He knocked down a big shot. And that's what you can expect out of him."

As you try to predict how the Celtics will do in the postseason, you have to factor Sam Cassell into the conversation. He has 115 playoff games under his belt, he will not be rattled, and if he makes shots like the one he made tonight in June, you may be forgetting about Pau Gasol, Jason Kidd and Shaquille O'Neal. Sam Cassell just might be the best late-season pickup of 2008.

"I'm gonna make shots," Cassell said. "You know me, I'm gonna make some shots."

Asked after Monday's game if he was more comfortable with Cassell than he was three hours earlier, Rivers' response was "I'm getting there."

"He hurt us a lot," Spurs coach Gregg Popovich admitted. "He did a great job, he made shots and that's what he does."

Sam Cassell makes shots. That's what he does.