This time last year Ray McCallum Jr. made perhaps the most important decision of his life.

He declared himself eligible for the NBA draft, giving up his senior year at the University of Detroit Mercy.

And looking back, there’s no question it was the right decision.

McCallum was selected in the second round (36th overall) of the draft by the Kings, and signed a three-year contract worth just under $2.3 million.

Then reality set in.

Although McCallum made the 15-man roster, he knew there were no guarantees. Playing time was minimal — if it came at all — and the transition of being a star on his college team to watching from the bench tested his resolve.

“Here I was, anxious before the first game,” McCallum said. “And I was (on the) inactive (list). I was sitting behind the bench. Sitting out? It’s different in the NBA. I just knew I had to stay working.

“To someone who’s always played, started, having to watch, to wait your turn was tough. I took it as a challenge. I worked hard every day to be ready.”

His chance finally came late in the season.

The Kings bought out Jimmer Fredette’s contract Feb. 27, which created more playing time for the remaining guards.

McCallum, however, still had to wait behind starting point guard Isaiah Thomas.

It wasn’t until March 26 — Thomas suffered an injury (quad contusion) — when McCallum got his first start against the Knicks. While McCallum didn’t light up the score sheet that night (10 points, five assists and six rebounds), he played 42 minutes 42 seconds.

He would start the next nine games.

“The second game I went against (Russell) Westbrook at Oklahoma City and I played like 46 minutes (45:42),” McCallum said. “Going against Westbrook taught me a lot. The next game I had 16 (points) and eight (assists) against Dallas and I played the whole game.

“It gives you confidence you can go against the best.”

In those 10 starts, McCallum averaged 13.8 points, 7.3 assists, 3.6 rebounds and 1.6 turnovers. Overall, he averaged 6.2 points in 45 games.