KANSAS CITY -- Lucas May was traded to the Arizona Diamondbacks for right-handed pitcher Andrea Pizziconi, the Royals announced Wednesday.

May, a catcher for Triple-A Omaha, appeared in 12 games for the Royals last season, hitting .189. In 25 games for the Storm Chasers this season, May was hitting .176 with a .263 on-base percentage and .329 slugging percentage. May had three home runs and 13 RBIs for the year.

Acquired from the Los Angeles Dodgers in the Scott Podsednik trade, May and Brayan Pena were going to be the Royals' catchers this season. But when the Texas Rangers made catcher Matt Treanor available, the Royals acquired him, sending May to Omaha.

Pizziconi, a 19-year-old signee out of Italy, had a 2.57 ERA in 49 innings pitched for the Missoula Osprey and Yakima Bears in 2010. The Royals assigned him to Rookie level Idaho Falls.

Catcher Cody Clark was reinstated from the seven-day disabled list to fill the Omaha roster spot.

Yost, McClure investigating Soria's issues

KANSAS CITY -- The sleuthing to solve the Joakim Soria mystery is on.

If detective fiction has Sherlock Holmes and Dr. Watson, baseball reality has Royals manager Ned Yost and pitching coach Bob McClure. And they are searching for the point in time where Soria got off track.

"Mac has gone back and looked at every one of his saves in the big leagues -- from 2007," Yost said. "There's not a lot of difference there. There are no glaring weaknesses. We don't find that he's tipping pitches anywhere. His arm's healthy. It's just getting back on track."

Overuse of the cutter and more reliance on Soria's staples -- the fastball and changeup -- is being studied. Yost said that McClure became concerned last season about Soria's frequent use of the cutter.

"Mac got a little fearful last year when he was throwing so many cutters, but he was racking up save after save after save. What are you gonna say?" Yost said.

Although Soria had 43 saves in 46 chances, disturbing side effects were duly noted.

"Higher pitch counts, fewer swings and misses and it all played into it," Yost said. "But when you're racking up 38, 39 consecutive saves, how do you tell a guy?"

Soria voluntarily stepped out of the closer's role, at least temporarily, after his fifth blown save on Memorial Day. Yost, though, already had decided to make that move before that game was over.

"Now we're back to the point where I think it's going to be a fairly easy fix," Yost said. "Getting your confidence back up to where you're invincible and bulletproof."

If he deduces correctly it will be, my dear McClure, elementary.

Hosmer, Francis earn Royals' May honors

KANSAS CITY -- Eric Hosmer's first month in the Major Leagues turned out to be a good one. He was named the Royals Player of the Month for May.

The rookie first baseman was called up May 6, going 0-for-2 with two walks, but quickly adapted to the big leagues. Hosmer led the club in batting average (.283), hits (28) and slugging percentage (.515), while hitting five home runs and driving in 17 runs. He also recorded multiple hits in eight of his 23 games.

Hosmer also came just one home run shy of tying a team record for home runs in a player's first month in the Major Leagues. Mark Quinn hit six home runs in September 1999.

Jeff Francis was named the Royals' Pitcher of the Month, recording four quality starts while going 2-2 in six games started. The left-hander pitched a team-high 40 2/3 innings and had an ERA of 3.98 for the month, striking out 22 while walking just 11.

Pitchers prepare for Interleague with BP

KANSAS CITY -- In preparation for upcoming Interleague series later this month, some of the Royals' starting pitchers took batting practice Wednesday.

Sean O'Sullivan was named by manager Ned Yost as the Royals' top-hitting pitcher, and he was joined by left-handers Jeff Francis and Danny Duffy in taking swings.

All three worked on bunting and shooting the ball the opposite way for hit-and-run situations, rather than swinging away.

"Right now, their thing with us is don't overdo it. Just go nice and easy," O'Sullivan said. "If one of us goes out there and tries to overswing, then the whole thing gets banked for all of us."

The Royals have just started allowing their pitchers to take batting practice in the last couple of days. Kansas City will resume Interleague Play on June 17, with a series in St. Louis, while also visiting San Diego and Colorado.

On the pitching side, O'Sullivan has been struggling with shoulder tendinitis, something that affected his last start in Texas. O'Sullivan pitched through 5 2/3 innings but allowed a career-high 10 runs on 15 hits. However, his work helped spell a bullpen that was called on to work into the 14th inning of an eventual win over Texas the night before.

"That last game, my shoulder felt real weak," O'Sullivan said. "But I knew our bullpen had been taxed in previous games, so I knew I was going to have to go out and keep going back out. I just tried to stay as mentally strong as I could, try and keep making pitches, even if I was going to give up runs, to try and keep my pitch count down."

Crown points

• The walk-off home run in Wednesday's 2-0 win over the Angels was the first of Billy Butler's career and the 60th in Royals history. All three of this year's walk-off homers have been against the Angels -- by Kila Ka'aihue on April 1, by Matt Treanor on April 3 and Butler's blast.

• The video review in the ninth inning was the fourth at Kauffman Stadium since the process was initiated in 2009.

• The combined shutout was the third for Royals pitchers this season. The first was April 16 against the Mariners, the second on May 20 against the Cardinals.

• Royals Charities will be donating more than $18,000 to the American Red Cross for tornado victims. The money will be sent to disaster relief in Joplin, Mo., and other areas hit by deadly tornadoes this spring. Volunteers from the Kansas City chapter of the American Red Cross have been collecting cash donations throughout this series at Kauffman Stadium.