| No. | Driver | Team | Engine |
|---|---|---|---|
| 4 | Matheus Leist | A. J. Foyt Enterprises | Chevrolet |
| 14 | Tony Kanaan | A. J. Foyt Enterprises | Chevrolet |
| 25 | Stefan Wilson * | Andretti Autosport | Honda |
| 26 | Zach Veach | Andretti Autosport | Honda |
| 27 | Alexander Rossi | Andretti Autosport | Honda |
| 28 | Ryan Hunter-Reay | Andretti Autosport | Honda |
| 29 | Carlos Muñoz * | Andretti Autosport | Honda |
| 98 | Marco Andretti | Andretti Autosport | Honda |
| 23 | Charlie Kimball | Carlin | Chevrolet |
| 59 | Max Chilton | Carlin | Chevrolet |
| 9 | Scott Dixon | Chip Ganassi Racing | Honda |
| 10 | Ed Jones | Chip Ganassi Racing | Honda |
| 18 | Sébastien Bourdais | Dale Coyne Racing with Vasser-Sullivan | Honda |
| 19 | Zachary Claman DeMelo [1] | Dale Coyne Racing | Honda |
| 19 | Pietro Fittipaldi [2] | Dale Coyne Racing | Honda |
| 63 | Pippa Mann * | Dale Coyne Racing | Honda |
| 17 | Connor Daly* | Dale Coyne Racing with Thom Burns Racing | Honda |
| 18 | Sébastien Bourdais | Dale Coyne Racing with Vasser-Sullivan | Honda |
| 24 | Sage Karam* | Dreyer & Reinbold Racing | Chevrolet |
| TBA | TBA * | Dreyer & Reinbold Racing | Chevrolet |
| 20 | Jordan King [3] | Ed Carpenter Racing | Chevrolet |
| 20 | Ed Carpenter [4] | Ed Carpenter Racing | Chevrolet |
| 21 | Spencer Pigot | Ed Carpenter Racing | Chevrolet |
| TBA | Danica Patrick * | Ed Carpenter Racing | Chevrolet |
| 88 | Gabby Chaves | Harding Racing | Chevrolet |
| 32 | René Binder [5] | Juncos Racing | Chevrolet |
| 32 | Kyle Kaiser [6] | Juncos Racing | Chevrolet |
| TBA | Buddy Lazier * | Lazier Partners Racing | TBA |
| 60 | Jack Harvey [7] | Michael Shank Racing | Honda |
| 15 | Graham Rahal | Rahal Letterman Lanigan Racing | Honda |
| 30 | Takuma Sato | Rahal Letterman Lanigan Racing | Honda |
| TBA | TBA * | Rahal Letterman Lanigan Racing | Honda |
| 5 | James Hinchcliffe | Schmidt Peterson Motorsports | Honda |
| 6 | Robert Wickens | Schmidt Peterson Motorsports | Honda |
| 7 | Jay Howard * | Schmidt Peterson Motorsports | Honda |
| 1 | Josef Newgarden | Team Penske | Chevrolet |
| 3 | Hélio Castroneves [8] | Team Penske | Chevrolet |
| 12 | Will Power | Team Penske | Chevrolet |
| 22 | Simon Pagenaud | Team Penske | Chevrolet |
* Only participating at Indy 500 (Round 6)
[1] Participating at rounds 1, 3–4, 7–8, 10–12, 14–15
[2] Participating at rounds 2, 5–6, 9, 13, 16–17
[3] Participating at rounds 1, 3–5, 7–8, 10, 12–13, 16–17
[4] Participating at rounds 2, 6, 9, 11, 14–15
[5] Participating at rounds 1, 4, 12–13
[6] Participating at rounds 2–3, 5–6
[7] Participating at rounds 1, 3, 6, 13, 16–17
[8] Participating at rounds 5–6
