Uehara signed a one-year, $4.25 million contract with the Red Sox in the offseason that included a vesting option for $4.25 million in 2014 if Uehara appeared in 55 games. Uehara has appeared in 54 games, making the option guaranteed after he makes his next appearance.
Incentives can push the deal to $5 million next season if Uehara finishes 35 games this year. The 38-year-old entered Monday with 23 games finished.
Uehara has pitched well out of the Red Sox bullpen, posting a 1.35 ERA while fanning 74 batters in 53 1/3 innings. The veteran took over the closer's role mid-season, and has recorded 12 saves in 15 chances. Uehara has overpowered opponents in his last 18 outings; he has not surrendered an earned run while striking out 25 and walking two.