The Diamondbacks agreed to re-sign free agent pitcher Aaron Heilman, according to Ken Rosenthal of FOX Sports (on Twitter). Heilman declined the D'Backs offer of arbitration earlier in the offseason after making $2.15MM last year.

The right-hander will get the chance to join some combination of Joe Saunders, Ian Kennedy, Daniel Hudson, Zach Duke and Barry Enright in the team's rotation. The D'Backs expressed interest in adding rotation depth earlier in the month, though it appeared then that any newcomers would arrive on minor league deals.

Heilman posted a 4.50 ERA with 6.9 K/9 and 3.3 BB/9 in 72 innings out of the bullpen for the D'Backs last year. The 32-year-old last started a game for the 2005 Mets, but he broke in as a starter in 2003.
I seriously doubt he returns as a starter.