PHOENIX -- The Diamondbacks' starting rotation appears to have settled in after a rough start, but on the theory that you can never have enough pitching, general manager Kevin Towers acquired right-hander Lucas Harrell on Monday.
Harrell, who had a strong season with the Astros in 2012 but has struggled since, is to join Class AAA Reno. He is expected to join recent pickup Randy Wolf, top prospect Archie Bradley, hard thrower Bo Schultz and Charles Brewer in the Reno rotation as the D-backs continue to assess a major league rotation that has a National League-low seven quality starts.
"We're looking for depth, for sure," manager Kirk Gibson said.
The Diamondbacks already have made two rotation changes after the loss of No. 1 Patrick Corbin to season-ending Tommy John surgery in spring training. Josh Collmenter was moved from the bullpen to take Randall Delgado's spot in mid-April and Mike Bolsinger was promoted from Reno to replace Trevor Cahill a week later.
"I think that we evaluate daily how we can improve our pitching. Our starting pitching has not been what we'd hoped it would be," Gibson said over the weekend.
"Our starters have been improved, but we are not where we need to be. You need to get to six and seven (innings) on a regular basis. We'll work toward that."
The starters have made strides. Collmenter went six innings in a 5-4 victory over the Phillies on Friday, Bronson Arroyo went 6 1/3 innings on Saturday and Brandon McCarthy struck out a career-high 12 in seven innings Sunday.
Harrell was 11-11 with a 3.76 ERA in 193 2/3 innings in 2012 while relying primarily on a sinking two-seam fastball. He lost his spot in the rotation last year in the second half of 2013, when he led the NL with 88 walks. After going 0-3 with a 9.49 ERA in three starts with the Astros this season, Harrell was outrighted to the minor leagues.
"I know a couple of years ago he had a really good year for Houston. Not so good lately, but the reports say he's still got a pretty good arm," Gibson said.
While the D-backs seem unlikely to make any more rotation changes in the near future, they do appear to have some options. Wolf pitched well in his most recent two starts at Reno, winning twice and giving up three runs in 11 innings.
Schultz, 2-2 with a 2.90 ERA, has shown remarkable command in his last four starts, with 20 strikeouts and no walks in his last 28 innings. Schultz was added to the 40-man roster last winter after being signed out an independent league two years ago.
Bradley has gone the other direction recently, a turn that came just after agent Jay Franklin suggested the D-backs failed to promote Bradley to the majors for service-time reasons. Bolsinger came up instead. Bradley has given up 12 runs in his last 12 1/3 innings while allowing 19 hits and eight walks.
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