MINNEAPOLIS -- Twins manager Ron Gardenhire said he's getting positive reports about how third baseman Danny Valencia has been doing at Triple-A Rochester.

Valencia was optioned to Rochester on May 9 after struggling with the Twins, as he hit .190 with a homer, triple and five doubles in 100 at-bats.

He's been faring better in the Minors, as he entered Monday hitting .268 with two homers and three doubles in 56 at-bats. He overcame an early slump and is hitting .325 with a .341 on-base percentage and .525 slugging percentage over his past 10 games.

"He's doing fine," Gardenhire said. "He's putting some good swings on the ball. He hurt his wrist, but got back at it. So he's hanging in there pretty good. He's driving the ball. I've watched a couple games and saw him bang one off the center-field wall on an 0-2 fastball."

Gardenhire added that Valencia has continued to make progress with his defense, which wasn't his problem in 27 games with the Twins this season.

"He was fine here and was a lot better and working hard at it," Gardenhire said. "We asked him to do that and he's been doing fine down there."

Twins celebrate Memorial Day with flyover

MINNEAPOLIS -- The Twins celebrated Memorial Day with a special pregame ceremony that featured a flyover of two vintage World War II aircraft over Target Field on Monday.

A P-51 Mustang and a P-38 Lightning both flew over the crowd while actor Reed Sigmund sang the National Anthem. The planes were both used in the filming of the upcoming movie Memorial Day.

Fans were also greeted at the gates by actors wearing WWII period uniforms from the movie.

Lt. Col. Ed Zinns served as the honorary flag raiser before Sigmund sang his rendition of the Star Spangled Banner. Zinns is a native of St. Cloud and spent 30 years in the military with the Army Air Corps and U.S. Air Force.

Walters giving boost to Twins' rotation

MINNEAPOLIS -- A day after P.J. Walters turned in his fourth straight quality start, Twins manager Ron Gardenhire continued to praise the right-hander on Monday.

Walters has been nothing but consistent since having his contract purchased from Triple-A Rochester on May 9. He has four of the club's 15 quality starts and has been the only Twins starter to go past seven innings in a game.

"It's what we were looking for," Gardenhire said. "When you call a guy up, you're hoping for a boost. And he's done that."

Walters labored a bit against the Tigers on Sunday, as he gave up seven hits and walked five over six innings but only allowed two runs because he pitched out of several jams. He was in line for the win before closer Matt Capps blew his first save of the season on a two-run homer by Miguel Cabrera in the ninth.

"We saw him battle through a lot of stuff and that was the greatest part about it," Gardenhire said. "He got through it all and never cracked. So it's good."

The tough part for Walters will be continuing to make adjustments now that more advance scouts have seen him pitch and there's more video available to opposing teams. But Gardenhire said Walters has the stuff to remain effective.

"They start knowing a little more about you when the reports start coming in," Gardenhire said. "But advance scouts have a lot to write about when you're pounding the zone with four pitches you can throw at any time. So even with reports, you know you're going to be in a battle with this guy."

Marquis clears waivers, becomes free agent

MINNEAPOLIS -- Right-hander Jason Marquis cleared release waivers and is now a free agent, Twins general manager Terry Ryan said Monday.

Marquis was designated for assignment on Tuesday after posting an 8.47 ERA in seven starts. He was placed on release waivers on Saturday after the Twins couldn't find a trade partner, but he wasn't claimed.

The Twins had the ability to option Marquis to Triple-A Rochester, but Ryan said they made the decision to let him become a free agent.

"I think we're going to move on," Ryan said. "I suspect that would be a mutual feeling. He doesn't need to pitch at Triple-A. I think it's fair to assume he's beyond that point. He might get signed by another club and be assigned to Triple-A to get him stretched out and acclimated, but I don't think that's what we should do."

The 33-year-old, who signed a one-year, $3 million deal before the season, struck out 12, walked 14 and gave up nine homers in 34 innings with the Twins.