Power Forward: Doug McDermott
Perhaps the most surprising addition to the starting lineup could be newcomer Doug McDermott. McDermott might seem like an odd choice over other options like Thaddeus Young, or even adding Lonnie Walker or Devin Vassell to the starting lineup and moving Johnson to the power forward spot.
That said, his sharpshooting and overall scoring ability will be desperately needed in the starting lineup. After all, McDermott's a career 40.7% 3-point shooter and ranks among the best shooters in the NBA. Additionally, he's surprisingly effective scoring inside the arc, converting on a stellar 64.1% of his 5.7 2-point attempts per game. His shooting efficiency should theoretically open up a ton of opportunities on offense for the Spurs' younger players.
McDermott will command tons of defensive attention when spotting up and open up more driving lanes for Murray, White, and Johnson. McDermott can also create shots for himself, though, by running off multiple screens and getting open for mid-range jumpers or threes. He's also capable of putting the ball on the floor, getting to the rim for layups, and is especially dangerous in dribble-handoff situations.
While there are defensive concerns with McDermott, playing alongside four already very talented defenders should help alleviate many of them, thus helping maximize his overall value. While he may not be the most skilled option at power forward, his fit within the rest of the starting unit makes him the best option for the team.