PHILADELPHIA -- The way things have been going lately for Vernon Wells, the Blue Jays' center fielder wasn't surprised by what happened in the third inning on Sunday.

Wells drilled the first pitch he saw from Florida's Josh Johnson back up the middle at Rogers Centre and seemed destined for a single. Instead, Marlins second baseman Dan Uggla made a spectacular diving grab and threw Wells out at first base, robbing him of a hit and sending him back to the dugout still searching for a way out of his persistent slump.

"I had no doubt he was catching it," Wells said with a smirk. "I had no doubt whatsoever. There wasn't even a thought in my mind that it was going to get into center field."

On Tuesday, Wells arrived at Citizens Banks Park looking for his first hit in a week. The center fielder entered the evening without a hit in his previous 17 at-bats -- a slump that dates back to June 9. Wells also had gone career-high 137 at-bats without a home run, posting a .197 average since he last cleared the fence in a game against the Angels on May 6.

The slump has been ugly, and no one is more frustrated than Wells. He is an integral piece to Toronto's offense, and that group's overall performance often is influenced by his production. Consider that in the 35 games since his last home run, in which Wells has driven in just seven runs, the Blue Jays have posted a 14-21 record.

At this point, Wells and the Jays are searching for any positives. On Sunday, Wells went 0-for-3, but hitting coach Gene Tenace saw an improved approach at the plate. Wells' struggles have involved problems with pitch selection and mechanics, and the slump has lasted so long that it likely has taken a mental toll on the center fielder.

That being the case, Tenace wants Wells to clear his mind and return to basics.

"This is a mental game up here. This is not a mechanical game," Tenace said on Tuesday. "Ninety percent of this game is in your head. If you've got all of these demons going through your head and you're trying to do this and you're trying to do that and you're thinking about mechanics, it's just going to snowball and everything is going to malfunction.

"We're trying to get him to get all of this stuff out of his head and just go back to baseball like you were taught. Hit the ball back up the middle of the field. Get the ball in the strike zone and get in position to hit it. He started that Sunday, so hopefully he can carry that out."

Overall, Wells is hitting .238 with five home runs and 28 RBIs through 65 games. After Sunday's game in Toronto, Wells said he felt more comfortable with his approach at the plate.

"It was lot better. My timing was a lot better," Wells said. "I was trying to be more active at the plate. I'm just kind of doing a lot of comparisons from three years ago and things like that -- where I was making contact, timing-wise, everything seemed to be reminiscent of that. It's just a matter of continuing to practice that and stay with that and not vary from it anymore."

In looking at video of his at-bats from the 2006 season -- when Wells hit .303 with 32 home runs and 106 RBIs and then was signed to a seven-year extension worth $126 million -- he noticed that his stance changed throughout the season. His base was more open at the beginning of the year and it closed more as the season wore on. Still, Wells said he used his lead foot better in getting his swing started, and he added that his hands consistently were in a better position to hit.

Tenace said he has analyzed footage of Wells' at-bats, but only from this season.

"I didn't see 2006. I look at what he's doing now," Tenace said. "I haven't gone back and looked at that. It still comes down to one thing. I can almost tell you what he's doing now, he didn't do in 2006. He's swinging at pitchers' pitches. He's not hitting his pitch. When he gets his pitch, he's not in a position to hit it."

On top of that, a slump can become mentally tough on a player when it lasts for weeks.

"All that comes into play," Tenace said. "When you're in a rut and you're a high-profile guy like Vernon, he feels the pressure. He's human. None of these guys want to go out and embarrass themself, I can tell you that. He's not any different than anybody else. He's as human as I am or anyone who's ever put a uniform on. He's trying his best. Sometimes maybe he's trying too much, too hard."

And, sometimes, positives can be found even when a struggling player goes 0-for-3, like Wells did on Sunday.

"He had a good approach," Tenace said. "You've got to start somewhere. I tried to explain that to him. I told him, 'Your approach to hitting has got to improve, and the results will come.'"