Here is an article on how the Red Sox addressed the two position question with Casey Kelly a few years back.
And another:But then the Sox lured him to baseball with their checkbook and a promise that he could both pitch and play shortstop in the minor leagues. The agreement between the player and club was that he’d have to choose one or the other at the end of last season.
The son of former major league catcher Pat Kelly (Toronto) spent last winter re-sculpting his physique at IMG Performance Institute. He spent his first full season of professional ball splitting time between the mound and shortstop.
The 30th overall pick in the 2008 draft began his first pro season out of high school as a shortstop in rookie ball and later spent time with the Class-A Lowell (Mass.) Spinners. In 2009, he switched to the mound and began the year as a pitcher for low Single-A Greenville (S.C.) and high Single-A Salem (Va.), going a combined 7-5 with a 2.08 ERA in 17 starts. In the second half of the year, the Red Sox took away the rosin bag, handed him a bat and he finished the year as a shortstop in Greenville and with the Gulf Coast League team in Fort Myers, Fla., hitting .222 with 16 RBIs in 40 games.