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6/23/2013 9:57 P.M. ET

Rookie Medina giving bullpen a boost

SEATTLE -- Against Oakland on Saturday night, the Mariners needed three pitchers to get through the first 6 2/3 innings. But Yoervis Medina came in and pitched the rest of the game without allowing a run, earning the win in the process.

It was just another new experience for the 24-year old from Venezuela, who has appeared in 25 games since making his MLB debut on April 16. Medina has posted a 2.70 ERA and picked up a pair of wins.

"It's a series of firsts for him, as it has been for so many of these guys," manager Eric Wedge said. "He does a nice job, especially once he works his way into it."

The emergence of Medina, along with the anticipated return of flame-throwing Stephen Pryor, could provide a significant boost to a struggling Mariners bullpen. Seattle relievers have given up the lead in five losses since May 29.

"It definitely gives me confidence," Medina said through translator Ryan Schmitz. "Every time I go in, I think, 'This time I have to do better than the last one.'"

Wedge commends Franklin's aggressive plate approach

SEATTLE -- In the seventh inning of Saturday's game against Oakland, the Mariners were down, 5-2, and hot-hitting rookie second baseman Nick Franklin was leading off for Seattle.

Franklin swung at a high fastball and popped it up to record the first out. But rather than correct the 22-year old for his mistake born from inexperience, manager Eric Wedge simply complimented him on his hustle. He avoided the coachable moment, because Franklin's aggression at the plate is exactly what he wants to instill in the rest of his team.

"I'm not going to get on him for swinging at a pitch that's up, because he's overly aggressive in that situation," Wedge said. "You can't say 'no fear' if you're going to bust their chops. You can't have it both ways, because there's no perfection. That's what people have to understand -- most importantly, the players."

The next time Franklin came to the plate, he hit a game-winning, two-run single in the eighth to give Seattle a two-run lead. Wedge believes Franklin's aggressive approach is a manifestation of his self-assurance, and that it's the type of confidence that allows a player to shrug off bad at-bats and hopefully, avoid slumps.

"That's the difference maker for him," Wedge said. "That's his attitude. He's a cocky kid, believes in himself. That is one thing that makes him different versus some of the others, without a doubt. That's a positive thing."

In second game back, Guti exits with leg tightness

SEATTLE -- Just one day after Franklin Gutierrez reminded the Mariners what they'd been missing with a home run and a double in his first game back from the disabled list, his health problems reared up once again in the Mariners' 6-3 win on Sunday. Gutierrez left the game in the seventh inning.

"His legs tightened up on him again, so we'll see how he feels in a couple days," manager Eric Wedge said.

The legs tightened when Gutierrez hit the center-field wall in the fourth inning while catching a fly ball from Jed Lowrie.

Keeping Gutierrez healthy and in the lineup has been tough over the last three seasons. The Mariners played their 400th game since the start of 2011 on Sunday. And Gutierrez, back in the lineup in center field for a second straight game, had played in just 149 of those.

"I'll tell you what, we've missed him more this year than anybody," Wedge said. "He's a separator for us. You can say what you want, but you saw it all spring. This guy is a difference maker."

If Gutierrez can stay in the lineup, it will give Wedge more options, both defensively and with his batting order. His presence Sunday allowed Wedge to give designated hitter Kendrys Morales a needed day off, until he pinch-hit in the 10th inning and came through with a home run. Raul Ibanez -- who had two homers of his own -- slid into the DH role, and Michael Saunders played left field.

If Gutierrez hasn't re-injured himself, Wedge will be cautious with him, something that will be made easier with the Mariners' three off-days in the next eight days.

Worth noting

• Danny Hultzen, the No. 2 overall pick in the 2011 Draft, has been promoted to Triple-A Tacoma. Hultzen had a rehab start in the Arizona League Saturday night, striking out eight batters in five innings.

• The Mariners have hit 14 home runs in 12 games against the A's this season. The injured Michael Morse has four of those homers.

• The Mariners announced the signing of eighth-round Draft pick Tyler Smith, a shortstop out of Oregon State. With the signing, Seattle has now come to terms with its top 20 draft picks.

Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. Jacob Thorpe is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.