SEATTLE -- When the Mariners acquired free-agent catcher Henry Blanco on June 14, the move was widely regarded as an attempt to provide a steadying defensive-minded mentor for rookie Mike Zunino, a prodigious hitter chosen by Seattle with the third overall pick in the 2012 First-Year Player Draft.

The plan was for Zunino to be the team's everyday backstop, while Blanco would be there to show him the ins and outs of professional baseball.

Blanco's presence would accelerate the youngster's learning curve as he taught Zunino the tricks of the trade, and the defensive-minded veteran could pick up a start here or there to help the rookie stave off the grind of a long season.

Things have not gone as planned, and the Mariners are doing just fine.

Blanco, a 41-year-old journeyman playing with his 11th Major League team, has been thrust into the spotlight after a Zunino broke the hamate bone in his left wrist while swinging the bat, sidelining him for weeks.

"When you sign with a team, you know your role. So obviously you've got to prepare yourself, and whatever they need you to do, you've got to be ready for any situation," Blanco said. "That's the type of guy I am. I come to the ballpark ready to play. If I'm in the lineup, I'm going to do my best. If I'm not, I'm going to do my best to cheer for my teammates."

As a stopgap measure, Seattle signed free agent Humberto Quintero, who was designated for assignment by the Phillies, on July 26 to split time with Blanco, and the duo has somehow managed to boost an already surging Mariners offense.

"Both of them are veteran guys. Obviously Henry is, and he knows his role coming in," acting manager Robby Thompson said. "I sat down with Humberto, and I talked about that also. [I told him] to always be ready and to make sure you're ready to go with the pitchers, the game plan and the preparation. They've both been doing an outstanding job with that."

Zunino's injury couldn't have come at a worse time for Seattle. After years of struggling at the plate, the Mariners were second in the American League in runs scored during July, and Zunino was a big reason why.

A position that had been a hole in the lineup since the days of Dan Wilson was suddenly a plus. Over the final 12 games leading up to Zunino's injury, the rookie hit .268 with a .770 OPS. More importantly, he was providing clutch hits, driving in the go-ahead run in his final three games, all wins by Seattle.

In eight games since Zunino went down, Blanco, who hasn't finished a season hitting above .190 since 2011, is batting .217 with eight RBIs and two homers, including a grand slam in the Mariners' 8-7 walk-off loss to the Red Sox on Aug. 1.

Quintero has been a revelation in his short time with Seattle, hitting .381 over six games, and hitting the game-winning home run in Wednesday's 9-7 victory over the Blue Jays.

"Q has been putting up some real good at-bats. He's doing a real good job back behind the plate," Thompson said. "Both of those guys have had some big hits for us, some big home runs for us."

Quintero in particular seems to be a good it in Seattle. While the Mariners love the offense he has given them during his short stay, Quintero says Seattle has given him even more in return.

"When I first came here, I felt like I'd been here for a long time," Quintero said. "The guys welcomed me, and I appreciate it. That had never happened before when I got traded. I feel like a family here; I love it here."

After winning nine of 10 games through the end of July and into August, the Mariners have lost eight of their last 12. The offense has returned to earth, and the pitching staff is showing signs of fatigue, with aces Hisashi Iwakuma and Felix Hernandez losing back-to-back games for the first time all season on Monday and Tuesday, respectively.

But against all odds, Seattle's catching corps has remained unaffected by the rest of the team's struggles, as Blanco and Quintero man the fort until Zunino returns.

"We're going to do the best we can. I'm going to give advice to [Quintero], I'm going to give advice to Mike and I'm going to give advice to myself just to keep going," Blanco said. "We've got a good thing going right now, and we want it to stay like that. We want it to keep going out there and compete with everyone that we have to play against."