The Detroit Tigers have offered salary arbitration to pitcher Jack Morris, preventing him from becoming a free agent, but his agent says the starting pitcher hasn't exercised his option for 1991.

By offering arbitration, Detroit prevented Morris from joining five other Tigers as free agents: pitcher Dan Petry, utility player Darnell Coles, relief pitcher Edwin Nunez, designated hitter Larry Sheets and outfielder John Shelby.Morris has until next Thursday to decide whether he wants to accept a salary of $2.1 million in the second year of a two-year contract. If he doesn't accept, he becomes eligible for salary arbitration in February.