TORONTO — For five seasons, Kyle Lowry has been the straw that stirred the Raptors drink.

He has been their best, most indispensable player, their leader on the court — and occasionally off of it — as they have won more regular-season games than any team in the Eastern Conference.

But the Raptors can’t bring back the pending free agent if they intend to bring back Dwane Casey for his seventh season as Toronto coach.

And the opposite is true, despite what Lowry said at the year-end availabilities on Monday. If he is welcomed back as an expensive signing, then Casey needs to be replaced as coach.

It’s not that the two can’t work together. They can — and they have. For the Raptors to progress as a more serious playoff team, to get more in line with the newer style of NBA basketball, to become more efficient, to take another step forward, the combination of a singular, stubborn point guard and a non-confrontational defensive-minded coach is simply repeating what happened this playoff season, last playoff season and the season before that.

You can win a lot of games with Casey coaching. And you can win a lot of games with Lowry as your point guard. But how many of them can you win with both when it matters most?

One thing has to change: Either the person calling the plays or the person running the plays.

NBA teams like to talk about being focused to win championships. Isiah Thomas did that in the Raptors’ formative years. Masai Ujiri does that now. The talk is earnest and forthright, but the reality is something else come playoff time.

No one in the East will beat Cleveland and no one in the West will beat Golden State and we know that with two rounds to go while 28 other teams talk about winning championships.

Tyronn Lue, the Cavaliers coach, talked about that very thing the other day. Lue mentioned a long list of great NBA players who never won titles because they had to beat Michael Jordan in order to do so. Today, you have to beat LeBron James or the Warriors’ paid-for juggernaut just to get there.

How many games you win in the season — that’s become almost irrelevant in the championship search.

The Raptors fell into the same trap many of us fell into this season. They watched the Cavaliers’ regular season. They saw how vulnerable the team looked defensively. They figured if not now, when? They made moves to make their roster deeper and stronger.

Then the playoffs began.

And in four games, the 51-win Raptors were hammered by the 51-win Cavaliers: King James averaged 36 points a game, with special attention on him. Worse than that, the Cavaliers scored 25 more points per game from the three-point line: 102 points in all.

The Raptors can’t do much about LeBron. No one can until age or injury catches up to him. The three-point shooting — they’ll have to address that in the off-season.

But the two games the Raptors competed best in — the pair at the Air Canada Centre — they played without Lowry, their best three-point shooter. They played three close quarters on Friday night. They played 36 close minutes on Sunday afternoon.

They played better without their best player than they did with him. Some of that is because they were at home. But in the 22 games Lowry missed this season due to injury — not counting the two he missed in the playoffs — the Raptors won 15 of 22 games. That’s .681 basketball — or a 55-win pace.

With Lowry, the Raptors won 36 and lost 24. That’s a 49-win pace.

And that’s without going into Lowry’s playoff history, where he is statistically among the worst shooters among prominent players in history — and shooting is one of the reasons why Toronto couldn’t play with Cleveland.

If the idea is to get more playoff-ready, you say goodbye to Lowry and try to find an alternative in the marketplace or develop your own. And if club president Ujiri determines he needs Lowry back and he can’t find anyone that compares to him, then he has to make a coaching change.

Why?

Because Casey’s style, both personally and professionally, has been to give Lowry all kinds of rope. He doesn’t get in Lowry’s face. He doesn’t call him out. He doesn’t sit him down on the nights when his play deserves a benching.

Casey’s strength in this case — as it has been through six remarkable seasons — is his belief in his players. He pushes them. He develops them. He finds a place for them. He tries to get his stars to play defence when it isn’t in their best nature. He won more games in his second year than he did in his first, more in his third than he did in his second. That has been his way until this season.

Casey has coached in 41 Raptors playoff games the past four years, with three of those ending with more questions than answers. He’s done remarkable work here and is as fine a man you’ll ever meet. But every coach has a shelf life.

The Raptors need to grow and thrive — with either a new coach or a new starting point guard. You can have one. You can’t have both.

ssimmons@postmedia.com