Lonnie Walker IV made a solid impression both on and off the court during training camp and preseason with the Boston Celtics. But when it came to trimming the roster for Tuesday's opening night, there wasn't enough room.

Because of the domino effect of Boston's offseason spending – the Celtics collected a total of over $500 million in extensions – the chances of retaining Walker diminished as Saturday's 5 p.m. ET deadline approached. Walker's original $2 million deal with Boston, had the 25-year-old not waived it, would have imposed an additional $10 million on the Celtics on top of an already hefty tax bill.

The ultimate trigger was inevitable, although Celtics president of basketball operations Brad Stevens made the right decision on paper when he signed Walker to an Exhibit 10 contract. Walker, a six-year veteran, a career 35.6% 3-point shooter and proven playoff player, was not the traditional caliber of player one would find on a non-guaranteed training camp invitational contract, but it paid off. Boston saw firsthand what Walker could do for the reigning champions, albeit in a small sample size.

The reception at training on Saturday in the Auerbach Center spoke for itself.

“A guy who’s been in the league a long time and has seen different environments. “He came in with his head down and just wanted to work and understand what it meant to play our style of basketball on both ends of the court,” Celtics head coach Joe Mazzulla told reporters, according to CLNS Media. “I thought he did a good job of executing that in the time he had and I thought he did a great job of being patient and executing the role that we needed him to play and I thought he Did a good job in the film room trying to get them to understand our system on both ends of the floor.”

Walker was a surprising name on the cold and bleak free agency market in late August. He averaged 9.7 points, 2.2 rebounds and 1.3 assists on 42.3% shooting from the field and 38.4% from three games and made 58 appearances (17.4 minutes) for the team last season Brooklyn Nets. In the three seasons prior to joining the Nets, Walker averaged 11.7 points in a total of two years with the Los Angeles Lakers and one year with the San Antonio Spurs.

When the Celtics called Walker's number and gave him permission to play in their penultimate preseason game against the Toronto Raptors, Walker delivered. He scored 20 points in 30 minutes and sank each of his first four 3-pointers.

“Great guy, he works hard and you can tell he has a lot of passion for the game and that’s always my type,” Derrick White said, according to CLNS Media. “I talk to him too much, I think. I try to give him space. I'm just kidding. We’ve been close since he was drafted in San Antonio, so that’s my guy and I’m sure we’ll talk soon.”

White and Walker spent three 1/2 seasons together with the Spurs, both playing under head coach Gregg Popovich's system. It didn't take long for White to speak highly of Walker, a longtime friend, after he joined the Celtics, and the possibility of the former San Antonio-raised veterans reuniting for Boston's title defense run isn't even a possibility Oblivion for everyone, only.

Walker now has two options at this point: either join the G League Maine Celtics and wait for the (expected) promotion to Boston, or sign a professional contract with another team. In any case, Walker is looking to increase his stock value – if an outsider doesn't sign him to a multi-year deal – before returning to free agency next offseason.

Shortly after the Boston front office made its decision, he shared a short but to-the-point message on Instagram.

“Will always bet on myself,” Walker posted on his Instagram Story. “It’s going to be one hell of a story.”

However, if the Celtics locker room had its way, the decision would be a no-brainer.

“I love Lonnie. I honestly feel like he’s a great player,” Luke Kornet explained, according to CLNS Media. “His energy and just his joy, passion and connection that he naturally possesses is great and I never really had the chance to get to know him until a few weeks ago and he was great to have around.” Honestly, it’s just fun to play and work with.”