Part of the Athletics' haul in the deal that sent Gonzalez to the Nationals over the winter, Milone posted a 2-1 record and 4.91 ERA in five spring outings (four starts).
Milone is scheduled to make his A's debut on Monday in the opener of a three-game set against the Royals.
"What we've seen out of him all spring is a guy who has great command," A's manager Bob Melvin said. "He seems to read hitters really well. He's got four pitches he throws to both sides of the plate, has a great changeup and his command's always good."
In his final two exhibition starts, Milone tossed six perfect innings against Oakland's Triple-A team, and followed up that performance with five scoreless frames against the Giants.
Melvin appreciates Milone's propensity to make hitters work.
"He's a very consistent guy who makes you string hits together in a row to make you have to beat him," Melvin said. "You're going to have to take what he gives you if you're going to go about beating him."
Milone made five starts for Washington last September, compiling a 1-0 record and 3.81 ERA over 26 innings.
The Royals are expected to counter with righty Luis Mendoza, who dazzled during Spring Training to the tune of a 4-0 record and a 0.47 ERA in six outings spanning 19 1/3 innings. Last year at Triple-A Omaha, he earned Pacific Coast League Pitcher of the Year honors by going 14-5 with a 2.03 ERA between the regular season and playoffs.
"I know it's the big leagues, I know it's different, I know the hitters are smarter," Mendoza said. "But I just try to do the same thing, keep the same consistency in my delivery and mix up my pitches more."
This is Mendoza's second chance at locking down a spot in a big league rotation. He began the 2008 season on the Rangers' staff, but made only 11 starts for Texas that season and posted an 8.67 ERA in 25 total appearances.
Mendoza has pitched fewer than 20 Major League innings since, but at age 28, he is penciled in as the Royals' No. 4 starter.
"A new team and a new challenge, and I just look forward to doing well and helping my team," he said.
Royals: Some sluggish starts for KC's bats
In taking the final two game of their opening three-game set against the Angels, the Royals plated a stellar 13 runs. But the Kansas City lineup wasn't exactly firing on all cylinders.
Left fielder Alex Gordon, the recipient of a recent long-term contract extension, is 0-for-13 with one walk and six strikeouts thus far. Lorenzo Cain, the team's new staring center fielder, is 1-for-11 with one walk and five strikeouts. Mike Moustakas, who the club hopes can hold down third base, is 1-for-11 with no walks and four strikeouts.
Moustakas has the trio's only extra-base hit, a home run on Saturday.
Jonathan Broxton has finished up both of the team's wins this season, including a dominant save in his first opportunity on Sunday.
The big right-hander, who signed with Kansas City as a free agent, has entered with a four-run lead both times. He gave up a run in the Royals' 6-3 win Saturday, then struck out three in a scoreless frame in Sunday's 7-3 victory. Broxton's fastball was clocked from 96 to 99 mph.
Manager Ned Yost has said the former Dodgers All-Star stands first in line to replace Joakim Soria, who is out for the season with Tommy John surgery. Greg Holland and Aaron Crow also could be in the mix.
Athletics: Cespedes off to scorching start
Rookie outfielder Yoenis Cespedes hit cleanup on Saturday, after batting fifth, seventh and sixth in his first three games.
The native of Cuba hit his third home run in four games on Saturday night. Overall, he's batting .308 (4-for-13), with seven RBIs and seven strikeouts.
"He's a power bat, and we'll continue to move [the lineup] around a bit, but I think he's swinging pretty well," Melvin said.
First baseman Daric Barton, who has been sidelined with a shoulder injury, was eligible to come off the 15-day disabled list on Sunday, but the club delayed that decision for at least a day. Barton instead started at first base for Triple-A Sacramento, and went 1-for-4 with a first-inning grand slam at Las Vegas.
When the A's choose to activate Barton, they'll likely have to designate for assignment one of the two first basemen already on their roster.
Brandon Allen and Kila Ka'aihue have each started two games at first base. Allen is 0-for-7 with five strikeouts, and Ka'aihue is 3-for-8. Both are out of options.
Oakland won five of its nine meetings with Kansas City last season.
A's second baseman Jemile Weeks hit his first home run of the year on Saturday. He hit just two last season in 97 games.