SEATTLE -- Eric Wedge has heard the argument that Justin Smoak has played long enough now that it's clear he'll never develop into a quality Major League hitter. But the Mariners manager isn't buying it.

Wedge sees significant optimism in Smoak's late-season hot streak this year as the 25-year-old hit .400 (22-for-55) over his last 15 games and .338 with five home runs in 23 games in September.

"I think it's the most real it's ever been in my time here," Wedge said prior to Monday night's series opener with the Angels. "Just because of the fundamental changes, and the consistency with which he's been able to sustain that swing, that approach, that mindset. The way he's taking pitches, the way the ball's coming off his bat from both sides of the plate. I'm as encouraged as I've ever been with him."

As for whether it's enough to change the offseason plans for what the Mariners need to do at first base?

"I'm probably the last person to talk to about that, because I've always felt so strongly about him, because of the work ethic," Wedge said. "He has championship character about him. He's a good teammate. I think he's tough. You just put all those things together, you have to believe.

"You trust in the process of baseball that it's going to come. The one thing I think it's always tough for people to understand, whether you're in the game or out of the game, it doesn't always come on our timetable."

Smoak has hit .222 in 1,247 career at-bats over two and a half years in the Majors, but Wedge said he's still developing.

"You don't know what kind of big leaguer you have until they've been up here for two and a half or three years," he said. "It takes that period of time to actually settle in. You look at all the great players -- and there's a few that get it right away, a few I could talk about on one hand that are first-ballot Hall of Fame guys -- but more times than not it just takes time because it's the big leagues and the highest level in the world.

"It's just not that easy. That's why patience is rewarded more so in this game than any other sport. He's in pretty good shape. You talk about Michael Saunders last year at this time -- which we weren't -- and you talk about Michael Saunders right now, that's a great example internally.

"But if you look throughout the game and say, 'This guy is a pretty good player,' well, look at their first year or second year. What did they do in their first 1,000 at-bats? They're not the same guy you're seeing right now. That's why you've got to trust your ability to evaluate and give them the time to do that."

Gutierrez sidelined with groin soreness

SEATTLE -- Mariners center fielder Franklin Gutierrez was not in the lineup Monday against the Angels as manager Eric Wedge said he's "day to day" with a sore left groin muscle that led to his removal from Sunday's loss in Oakland.

Of course, there are only two days remaining in the season after Monday, but Wedge doesn't want to just write Gutierrez off yet as he has hoped to see the former Gold Glove winner in the same outfield with Michael Saunders and Casper Wells down the stretch.

Not to mention, he wants Gutierrez to get as much as possible out of a season in which he's played just 40 games due first to a partially torn oblique muscle and later to a concussion.

"I'm a big believer you have to fight to stay on the field," Wedge said. "If he has a chance to play another game, we're going to get him in there. If it doesn't make any sense, then we won't."

But Wedge said Gutierrez was still "really sore" on Monday after feeling the leg tighten up while running the bases Sunday, when he doubled in his first two at-bats.

Mariners bullpen fighting to the finish

SEATTLE -- After giving up 12 earned runs and four home runs in 7 1/3 innings in three losses to the A's over the weekend, it's clear the Mariners bullpen is wearing down after an impressive run for most of 2012.

Left-hander Lucas Luetge, who had a 1.86 ERA through the first four months of the season, has given up 19 hits and 12 runs in 11 2/3 innings for a 9.26 ERA in August and September.

Luetge, in his first year in the Majors as a Rule 5 Draft pick, said he doesn't feel worn out by his 63 appearances but doesn't ignore the obvious, either.

"I don't think so, but obviously the numbers in September don't lie," said Luetge, who allowed a two-run blast to Josh Reddick in Sunday's loss. "I guess maybe my body isn't used to this, but it's just me needing to make a small adjustment these last three games and finish it out strong."

Charlie Furbush struggled Friday when he gave up two walks and a single without getting an out to fuel the A's four-run seventh, though he came back Sunday with a better inning.

"It was just a rough day at the office," Furbush said. "I felt a lot better obviously [Sunday]. It's not really something I want to dwell upon. That's not going to get me anywhere. Once it happened, I wasn't pleased with myself. You never want to create situations that somebody else has to clean up."

What did he do better Sunday?

"I think I just really made myself aware of what happened and that wasn't acceptable," he said. "I need to keep the bulldog mentality, even when things aren't going my way. I want to at least give myself my best shot and that really wasn't happening that day."

Shawn Kelley said the heavy use in the bullpen isn't an acceptable excuse. He was kicking himself after giving up the go-ahead home run to Yoenis Cespedes on Sunday.

"It's different, but at the same time if we want to make a stretch run at the playoffs, we're going to have to be pitching our best this time of the year," Kelley said. "There's no excuse being tired. Hitters, pitchers, we've all been through a long grind. But I felt pretty good out there. I just have to go out and execute pitches and get my job done. I had one job, to get Cespedes, and I knew that and I didn't get it done."

Manager Eric Wedge said the experience is all part of the club's growing process.

"Our bullpen has done a great job all year long," Wedge said. "I'm sure they're feeling it a little bit, just in regard to the number of appearances they've had and the workload. But the overall atmosphere and games in which they're playing, I think it's important for them. It's going to come back to them. It's going to be that much more comfortable when they get in more meaningful games for us late in the year."

Worth noting

• Wednesday's season finale against the Angels will be played at 3:40 p.m. PT, not the 7:10 p.m. start time shown on most schedules.

• When the Mariners didn't hit a home run in Sunday's 5-2 loss in Oakland, it snapped a streak of 18 consecutive games with a long ball that ranked as the second-longest run in team history. The record of 19 straight games with a home run from Sept. 7-27, 1999, still stands.