Reynolds, a left-hander, went 3-1 and had a 4.40 ERA with 51 strikeouts and 17 walks last season with the Rockies in 57.1 innings pitched. It was the 28-year-old's second full season in MLB. He is 5-3 in his career and holds a 3.93 ERA.
The Diamondbacks' addition to the bullpen is tied for third among left-handed pitchers in MLB games played over the past two years.
Wheeler made his MLB debut for the Diamondbacks this past season and played in 50 games for the ball club. The 24-year-old battled .239, hit one home run and recorded 10 RBI. With Triple-A Reno last year, Wheeler battled .351 and had 90 RBI.
Wheeler was a fifth-round pick by Arizona in the 2009 draft and became expendable with the infield depth after the Diamondbacks acquired third baseman Chris Johnson.