| 2010-11 | NCAA | UMass (Amherst) | 34 | 6 | 8 | 14 | 12 | -5 | -- | -- | -- | -- | -- | -- |
| 2013-14 | AHL | Wilkes-Barre/Scranton Penguins | 2 | 0 | 0 | 0 | 0 | 0 | 15 | 6 | 5 | 11 | 0 | 4 |
| 2014-15 | AHL | Wilkes-Barre/Scranton Penguins | 58 | 20 | 25 | 45 | 8 | 0 | 8 | 5 | 7 | 12 | 2 | -1 |
| 2015-16 | AHL | Wilkes-Barre/Scranton Penguins | 30 | 7 | 29 | 36 | 4 | 8 | -- | -- | -- | -- | -- | -- |
| 2015-16 | NHL | Pittsburgh Penguins | 44 | 7 | 3 | 10 | 8 | -1 | 23 | 4 | 6 | 10 | 8 | -1 |
| 2016-17 | NHL | Pittsburgh Penguins | 61 | 23 | 30 | 53 | 22 | 24 | 22 | 2 | 5 | 7 | 4 | -5 |
| 2017-18 | NHL | Pittsburgh Penguins | 79 | 18 | 12 | 30 | 10 | 2 | 12 | 0 | 2 | 2 | 2 | -2 |
| 2018-19 | NHL | Buffalo Sabres | 78 | 14 | 20 | 34 | 12 | -18 | -- | -- | -- | -- | -- | -- |
| 2019-20 | NHL | Buffalo Sabres | 55 | 9 | 10 | 19 | 8 | -4 | -- | -- | -- | -- | -- | -- |
| 2019-20 | NHL | Pittsburgh Penguins | 8 | 1 | 3 | 4 | 2 | -1 | 4 | 0 | 2 | 2 | 2 | 3 |
| 2020-21 | NHL | Washington Capitals | 53 | 14 | 8 | 22 | 14 | -1 | 5 | 1 | 0 | 1 | 2 | -4 |
| 2021-22 | NHL | Washington Capitals | 71 | 19 | 24 | 43 | 14 | -2 | 6 | 0 | 1 | 1 | 0 | -2 |
| 2022-23 | NHL | Washington Capitals | 82 | 15 | 22 | 37 | 22 | 9 | -- | -- | -- | -- | -- | -- |
| 2023-24 | NHL | Tampa Bay Lightning | 57 | 4 | 11 | 15 | 12 | -3 | -- | -- | -- | -- | -- | -- |
| 2024-25 | AHL | Syracuse Crunch | 59 | 20 | 41 | 61 | 23 | 15 | 2 | 1 | 0 | 1 | 0 | 1 |
| 2024-25 | NHL | Tampa Bay Lightning | 5 | 0 | 0 | 0 | 4 | -2 | -- | -- | -- | -- | -- | -- |
| 2025-26 | NHL | New York Rangers | 46 | 2 | 9 | 11 | 10 | -1 | -- | -- | -- | -- | -- | -- |
| NHL TOTALS | 639 | 126 | 152 | 278 | 138 | 2 | 72 | 7 | 16 | 23 | 18 | -11 |