The contract includes additional incentives based on innings pitched, according to Ken Rosenthal of The Athletic reports.
Hill, who turns 42 in March, is entering his 18th MLB season. He split the 2021 campaign between the Mets and Rays, making 31 starts with a 3.86 ERA and 150 strikeouts.
This will be Hill's second stint with the Red Sox after he pitched parts of three seasons from 2010-12 in Boston as a reliever. He has pitched in 324 games and made 195 starts in his career.