The Rangers selected Jankowski's contract Wednesday, Evan Grant of the Dallas Morning News reports.
He'll fill the vacancy left by Leody Taveras, who is still working back from a left oblique strain and will open the season on the injured list. Jankowski, 31, signed a minor-league contract with Texas in January after batting just .164 with a .445 OPS in 44 games last season between the Mets and Mariners.