The Boston Red Sox are paying James Paxton $10 million in 2022 to rehab from Tommy John surgery and possibly return to start games at some point during the second half.

There’s no guarantee he will pitch. He might miss the entire season.

The important part of this contract is the two-year option. If the Red Sox feel Paxton is healthy after the 2022 season, they will trigger a two-year option worth up to $25 million that will keep him with Boston for both 2023 and ’24.

Starting pitcher James Paxton, right, reacts on the mound after an injury during the second inning of the Seattle Mariners’ baseball game against the Chicago White Sox on April 6, 2021, in Seattle. Paxton left the game and underwent Tommy John surgery and missed the remainder of the season. AP file photo

It’s not unheard of for a club to give a rehabbing pitcher a contract knowing that he might spend the entire first season rehabbing.

The Rays negotiated something similar with Nathan Eovaldi in 2017 albeit for much less money.

Tampa signed Eovaldi to a one-year, $2-million contract in February 2017. The deal included a club option for 2018 that allowed Eovaldi to earn up to $3.5 million in incentives.

Eovaldi did not pitch at all in 2017 while he rehabbed from a second Tommy John surgery that he underwent in August 2016. He was at an early stage in his rehab when he signed the contract, making 25 throws into a sock attached to his arm three times a week, per MLB.com.

The deal certainly worked out for the Rays. Eovaldi returned to pitch well in 2018 (3.81 ERA, 22 outings, 21 starts). Tampa traded him midseason to the Red Sox who he helped lead to a World Series championship.

Giving Paxton $10 million knowing there’s a chance he might not pitch in 2022 (or pitch very little) makes it seem like the Red Sox are willing to exceed the Competitive Balance Tax threshold in 2022. Chief baseball officer Chaim Bloom wouldn’t be adding a $10 million average annual value contract if ownership had given him a mandate to stay under the base threshold in 2022.

A new Collective Bargaining Agreement will determine the base threshold.

Paxton also throws hard like Eovaldi.

The lefty left his first start of 2021 injured. He did not pitch again before undergoing surgery later in April.

His fastball velocity declined considerably in his five starts in 2020 as he dealt with a flexor strain. His four-seam fastball averaged 92.1 mph, per Baseball Savant.

But his four-seamer averaged 95.4 mph in 2019, 95.4 mph in 2018, 95.5 mph in 2017 and 97.5 mph in 2016. So when he’s healthy, he throws hard and mixes in an effective curveball and cutter. He also occasionally works in in a rare changeup.

He held opponents to a .178 batting average and .168 expected batting average when he threw his curveball in 2019.