Citing sources close to the team, The Seattle Times said an announcement about Hernandez's contract extension could come before Wednesday.
Contract talks with the Mariners ace were held up last week when a physical exam revealed an unspecified "elbow issue" with the durable right-hander, but sources indicated the injury wasn't seen as serious.
Hernandez has tentatively agreed to a seven-year, $175 million extension, Fox Sports reported.
The seven-year veteran threw a perfect game last season while compiling a 13-9 record with a 3.06 ERA over 33 starts. He struck out 223 batters over 232 innings.
For his career, the five-time all-star has compiled a 98-76 record over 238 games -- all starts -- with a 3.22 ERA and 1,487 strikeouts.