Jan 22, 2010 8:57 AM EST

The Mariners and pitcher Felix Hernandez have finalized their five-year, $78 million deal.

The contract will keep Hernandez in Seattle through the 2014 season. He said personal growth allowed him to grow as a player last season.

"It's the maturity, man. I had my kids and it made me grow up," Hernandez, 23, said Thursday.

He went 19-5 with a 2.49 ERA in 34 starts in 2009.

Via ESPN