OAKLAND -- Right-handed pitcher Joey Devine lost command of his fastball during his last three outings. On Wednesday, something else was out of his control, as the A's optioned the reliever to Triple-A Sacramento.

To take Devine's spot on the 25-man roster, the A's recalled righty Trystan Magnuson from Sacramento for his third stint with the big league club this season.

Devine started the season with the River Cats, but he was promoted to the A's on May 20. He sported a 2.14 ERA with seven holds in his first 23 relief appearances, but Devine struggled on the club's recent road trip.

In those games -- one against the Tigers and two against the Yankees -- the righty allowed four runs on three hits over a combined two innings of work while walking four batters.

"Joey was struggling with his command, and his role, being the seventh-inning guy, it's a difficult one to struggle with your command in," A's manager Bob Melvin said, admitting that Devine's last three outings played a role in the decision. "We figured it was best to work on these things in the Minor Leagues and get his command back there. This is a guy who's very important to us and we need, and has been very good for us in that role, so he'll work on that there."

In two prior spells with the A's this season, Magnuson made three appearances out of the bullpen that totaled 6 1/3 innings and resulted in an 8.53 ERA.

Only one of those outings was with Melvin at the helm. The righty tossed 3 1/3 scoreless innings against the Marlins on June 30, and Melvin was impressed with what he saw out of the rookie.

"It was hard to send him down," Melvin said. "A guy goes out there and gives you 3 1/3, and you have to send him back down. First impression, for me, was great. The velocity was more than I anticipated -- saw some [94-mph pitches] and I think a 95. He was ahead in the count, mixed his pitches, and he's a tall guy with a downhill plane."

Melvin anticipates a similar role for Magnuson out of the bullpen this time around, as he is the one reliever on the Oakland roster who can eat up innings, if necessary. Magnuson's long-relief potential, combined with the move to send Devine back to the Minors, means Melvin will move rookie right-hander Fautino De Los Santos into the seventh-inning role.

In 10 appearances (12 1/3 innings), De Los Santos has given up just four earned runs while striking out 18, and he entered Wednesday having held opponents to a .125 batting average.

"He's pitched well for us and has plus stuff, and you can see his confidence growing," Melvin said. "The fact that Devine is not here, there's a chance that he can pitch a little deeper into games and have a more prominent role."

Pennington downplays hot stretch since break

OAKLAND -- No one in the league has been hotter than Cliff Pennington coming out of the All-Star break.

The A's shortstop entered Wednesday leading the Majors with a .500 batting average this half and was riding a career-high 10-game hitting streak, all while helping the A's play some of their best offense of the season.

Pennington ran that streak to 11 games with a hit in three at-bats during Wednesday's 13-4 rout of the Rays.

"He's been hot, no question about it," said A's manager Bob Melvin. "I hope that continues. He's playing with a lot of confidence and swinging well from both sides of the plate, so I'm sure he -- and us as well -- hopes that continues and rides this streak. He's doing a nice job."

A nice job might be an understatement. The switch-hitter has eight RBIs and has drawn five walks since the break. He has knocked a pair of home runs, hit three doubles and scored eight runs of his own.

Melvin said it looks to him like Pennington has shortened his swing, but the shortstop said he hasn't changed anything in his approach.

"It's just balls are falling in and I'm seeing the ball well," Pennington said. "I'm just trying to have good at-bats. When I hit them hard, they're not going at somebody. Some of it is stuff that's out of your control."

What is in his control, though, is his confidence at the plate, which is soaring during one of the best short stretches of offense in his four Major League seasons. Although his bat is hot and his esteem is high, Pennington downplayed his surge.

"If it lasts for a month, then we can talk," Pennington said.

A's skipper Melvin opposed to more replay

OAKLAND -- Don't count A's manager Bob Melvin among those who would like to see more instant replay instituted in Major League Baseball.

The skipper is a fan of the human element of the game -- even after watching the controversial ending to Tuesday night's 19-inning marathon between the Braves and Pirates, in which Julio Lugo was ruled safe at home plate by umpire Jerry Meals after Pirates catcher Michael McKenry attempted a swiping tag for a 4-3 Atlanta victory.

"I did see the play, and I was surprised at the call," Melvin said.

But that doesn't mean Melvin would like to increase the use of instant replay. He thinks the system is fine with the way it's currently set up, reviewing only home-run calls.

"There's always been a human element in baseball with umpires, and that's just part of it," Melvin said. "If you start opening that up for different plays, then there's no stopping and everyone's going to want it for everything, and next thing you know, you're going to have sensors out on the field and everything like that, and that's not the way baseball is supposed to be played."

Worth noting

• David DeJesus was given the day off and was out of the lineup Wednesday. That gave Ryan Sweeney the nod in right field, his ninth start on that side of the outfield this season. After Wednesday's three-hit performance, Sweeney is 9-for-20 in his career against Rays starter James Shields.

"Shields is no day at the beach, but he does have some success off of him," said Oakland manager Bob Melvin.

• After being limited to designated-hitter duties for the first two games of the series with a stiff neck, Josh Willingham returned to left field for Wednesday's matchup, moving Hideki Matsui back to the DH role. Willingham doubled and scored a run, and Matsui recorded his eighth career five-RBI game.