Joe Nathan’s two-year contract with the Rangers includes a $14.75 million guarantee and the chance to turn the 2014 club option into a player option, according to a major-league source.

Nathan will earn base salaries of $7 million in 2012 and 2013. The Rangers’ option for the third year is worth $9 million, with a $750,000 buyout.

Nathan can earn up to $1 million in incentives based on games finished in 2012 and 2013. Whatever he earns in ’12 will apply to the base salary in ’13.

In other words, if he makes an additional $750,000 based on games finished in 2012, his 2013 base salary will jump to $7.75 million. (And he still could earn another $1 million in incentives in 2013.)

If Nathan finishes a certain number of games in ’13, the source said, the $9 million option for ’14 will become his and not the team’s.

Nathan saved 14 games with a 4.84 ERA in 44 2/3 innings this year, after missing the entire 2010 season because of elbow surgery.

-- Jon Paul Morosi