Wolf, who signed with the D-backs last month, went 5-1 with a 4.50 ERA in six starts for Triple-A Reno, a span of 34 innings. He struck out 35 batters and walked 18 for the Aces.
"I think he enjoyed his stay down there in Reno, and he pitched very well, but at this point in time and the way our starters were throwing, we didn't want to put him in the bullpen," D-backs general manager Kevin Towers said. "I think he wants to start. We didn't see anybody we wanted to take out, so he opted to take his out [clause]. We just decided to go with younger players."
D-backs starters are 6-2 with a 3.01 ERA with six quality starts in the first 11 games in May. What's more, rookie Chase Anderson allowed one run and two hits in 5 1/3 innings against the White Sox on Sunday in his big league debut.
"[Wolf's] name came up in some of our discussions, but we felt where the club was at, is the message to your fan base when you're losing to bring up an aging veteran? Is that really the direction this organization should be heading?" Towers said. "We felt it was better to give the opportunity to some of the young guys that have been performing in the Minor Leagues."
Wolf is 132-117 with a 4.20 ERA in 376 appearances (368 starts) over parts of 14 seasons. He didn't pitch in the Major Leagues last year because of Tommy John surgery, and last pitched in the big leagues for the Brewers and Orioles in 2012.