OAKLAND -- David DeJesus is never without a smile, even while treading uncharted territory through the worst offensive campaign of his nine-year Major League career.

"You see him every day, and you wouldn't know that he's struggling," manager Bob Melvin said. "He's got such a positive outlook."

While that might make the woes slightly easier to work through, it doesn't make them disappear. In fact, DeJesus called this year "the toughest mentally."

"For sure," he said. "I'd say in my life, really. It's never been like this. It's one of those things you never know how you truly are until you go through something tough. This was a tough year, but I feel, mentally, I've been able to deal with it really well, and now it's just going out there and performing to my known abilities next year."

With just 12 games remaining following Thursday's contest against the Tigers, there's only so much DeJesus can do this year to boost his .232 average, which ranked sixth lowest in the American League entering the day.

Though he realizes time isn't on his side, DeJesus plans on using what's left of it to produce a strong finish, which would bode well for the free agent-to-be. He took a big step toward that end on Thursday, cracking a three-run homer in the first inning off Detroit's Max Scherzer.

"There's a whole bunch of stuff I'm going through right now," DeJesus said. "It's been a process all year long. Right now I feel like I'm working on the right things, and I'm just going to keep holding to them."

There are several theories circulating around DeJesus, who hit below .281 just once in eight seasons with the Royals. Perhaps he's best suited in the No. 2 spot, where he's batting .361 with a .425 on-base percentage in just 10 games this year. But he was pegged as the A's No. 3 hitter at the start of the season, posting a dismal .193 average there.

That slow start, Melvin believes, could still be affecting the veteran, who has since been mainly utilized in the fifth or sixth spot, as Jemile Weeks' midseason presence at the top of the lineup paved the way for a domino effect below him.

"For the most part, when guys have bad years, guys get off to a bad start and it's tough to get going," Melvin said. "And the deeper hole you dig for yourself, the tougher it is to get out of it."

Around DeJesus, fellow pending free agent Josh Willingham has offered Oakland what DeJesus says is "just the type of player they wanted from him." Willingham entered Thursday with a team-leading 26 home runs and 91 RBIs. And Coco Crisp, who will also be a free agent, is tied for second in the AL with 40 stolen bases.

Of the three, DeJesus appears the least likely to return, though A's general manager Billy Beane has made it clear those decisions will wait until the season has concluded.

Melvin playing it safe with Weeks

OAKLAND -- Jemile Weeks walked into the A's clubhouse on Thursday expecting to find his name in the lineup, but the rookie second baseman was instead given an extra day to rest his left leg.

Weeks is still experiencing leftover effects of cramps that surfaced on Saturday in Texas, and combined with his past injury history, manager Bob Melvin thought it best to take the cautious route.

"He probably could play, but he's a guy that uses his legs, and it's a big part of his game," the A's skipper said. "I know he wants to get back out there and play, but he's probably better served to give it one extra day. He's been playing awfully hard and awfully aggressive, and probably more so than he has in his career, which is a credit to him, but we don't want to take this thing too far."

The 24-year-old Weeks has started 84 of the A's 89 games at second base since he was selected from Triple-A Sacramento on June 7, making for a grind that's been eased by his manager.

"Everybody feels nicks and knacks at this point of the season, but for the most part my body feels pretty good," Weeks said. "Bob kind of pulled that extra desire to be ready every day out of me, even more than it was before, and I appreciate him for that. That's helped me tremendously.

"There are obviously days out there when things haven't been going great, but you want to go out there and work through those bad days and try to fix them, not by taking that day off."

Eric Sogard made his second straight start at second base in Weeks' stead for the club's series opener against the Tigers on Thursday.

Weeks is expected to be back in the lineup Friday.

Quad keeping Sweeney out for time being

OAKLAND -- A day after suffering a Grade 1 strain to his upper left quad, Ryan Sweeney was simply deemed day to day Thursday by manager Bob Melvin, who left open the possibility of his return by season's end.

"We're always hopeful for that," Melvin said. "It usually takes a couple of days to figure out where you are with something like that, but I know he's hopeful to try to get back, as well."

In the meantime, Sweeney was expected to stay off the field Thursday and remain in the trainer's room to receive treatment in an effort to further the rehab process.

It's already been a frustrating season for the outfielder, who was relegated to a bench role this season after spending each of the past two years as an everyday player.

Sweeney initially departed Wednesday's game after grounding out in the sixth inning. He was replaced by September callup Jai Miller, who served as a bench player for Thursday's contest, with Coco Crisp making his way back into the lineup after missing eight of the last 10 games with right ankle soreness.