Willis is said to be "probably not too happy about it,'' according to a friend.
Considering the struggles of the other Tigers starters, there's no certainty Willis would remain in the bullpen for too long. He was signed to a three-year, $29-million deal shortly after the Tigers acquired him in the eight-player deal that also brought
Willis has been on the disabled list with a right knee injury since April 13. He threw a bullpen session Tuesday, and the Tigers have been weighing where to put him.
Willis, who had a 1-1 record and 4.41 ERA before going on the D.L., was plagued by control problems in spring training and early in the year. But the Tigers' rotation has been awful in his absence.