With Harrison under contract, the Rangers have three of their starting pitchers signed for at least four more seasons with another under control for at least that long.
Japanese ace Yu Darvish last year signed a $56 million, six-year deal with the Rangers and then won 16 games as a major league rookie. There are provisions in his contract that could allow the 26-year-old righty to become a free agent after the 2016 season.
Texas has 26-year-old left-hander Derek Holland under contract through at least 2016, with club options for two more years after that. Holland is planning to pitch in the WBC this spring.
Alexi Ogando, who won 13 games as a starter and was an All-Star in 2011, is returning to the rotation this spring. The 29-year-old is under Rangers control for at least four more seasons, including his arbitration-eligible years.
"Those are four solid pitchers who are in their prime who will be part of the Texas Rangers family for the foreseeable future," Levine said. "We'll take our chances if we're going to build around that core of men that we'll be able to compete for championships in the American League for this time and in the future."