The moment you doubt Gary Sheffield, he will hurt you.

The Fantasy-playing community is only now finding out what opposing pitchers have known for years. His furious bat waggle, his menacing scowl, his propensity for hitting the ball almost too hard -- it all becomes more pronounced, more intense, more over-the-top when people write him off, until one day his swing of the bat rains not fly balls, but a fine powder all over the infield.

Rosin? Nope, baseball -- the whole of it -- shattered into tiny, easily inhalable pieces.

Cover your mouth before you cough.

Sliders These guys haven't just gotten hot or cold. Their recent play has caused their Fantasy appeal to "slide" one way or another.

Gary Sheffield, OF, Mets

He had just posted his worst OPS since his rookie season. He was coming off a shoulder injury and his 40th birthday, giving every indication his days as a rosterable Fantasy option had reached an end. He was an echo, an afterthought, a person as relevant to Fantasy Baseball as Joe Inglett or Don Knotts.

But for some reason, about midway through this spring, I had a renewed interest in Sheffield.

Don't get me wrong: It didn't last long. No, the Tigers abruptly put an end to that by releasing him late in March. But before then, I remember reading a story on MLB.com that gave a possible explanation for Sheffield's struggles last year.

Actually, his struggles began after the All-Star break in 2007, when on July 21, he collided with Placido Polanco while chasing down a fly ball, injuring his shoulder. At the time of the incident, he had a .306 batting average and 23 home runs in 343 at-bats. Afterward, he had a .171 batting average and two home runs in 151 at-bats.

Obviously, it had an effect, and then when he produced his career-low numbers last year, people assumed the effect carried over. And it did, just not in the way everyone thought.

Sheffield didn't have irrevocable damage to his shoulder; he simply developed some bad habits. After the injury, his shoulder hurt. He didn't want to test it, so he lowered his hands, waggling his bat in front of his chest instead of his neck. It changed everything, at least according to Tigers hitting coach Lloyd McClendon.

For as much as it sounded like wishful thinking, it also had a certain logic to it. I found myself paying closer attention to Sheffield's at-bats, hoping to see some sort of rejuvenation.

And then the Tigers released him. So much for all that, I thought. If they didn't buy into McClendon's reasoning, why should I?

Because one-third of the way into the season, Sheffield has a .932 OPS -- that's why.

Look, I don't want to go overboard reviewing Sheffield's numbers. I think we can all accept he ranks right up there with Manny Ramirez, Alex Rodriguez and Albert Pujols as one of the best right-handed hitters of the last 15 years. That's not to say he'll perform at that level now, at age 40, but if he performs at even a fraction of it, you'll want him on your Fantasy team.

Don't make the mistake of writing off this latest performance as nothing more than a hot streak. Sheffield was consistently bad during the year and a half after the incident, so the fact he's showing any signs of life convinces me he made a change that can continue over the season's entirety.

Just as long as Polanco stays out of his way.

At this point, I wouldn't hesitate to add Sheffield -- or start him -- in any league. The Mets clearly see him as a focal point of their lineup, batting him cleanup, so as long as he stays healthy, he'll get all the at-bats he needs.

Jeff Francoeur, OF, Braves

You want someone to write off? Try this guy.

We've all heard the glowing reports on Francoeur for years now -- none more Pollyannaish than this spring, when he adjusted his stance and talked hitting with Chipper Jones and Terry Pendleton. He probably could have a clairvoyant put him in touch with Babe Ruth, and it wouldn't have made a difference. He is what he is: a likable, personable guy who can't hit at the major-league level.

For all his supposed adjustments, for all the time and effort he put into making himself better, he's only gotten worse, posting a lower OPS (.615) through Monday than he did in his disastrous 2008 campaign (.630).

Yeah, it gets worse. As a slugger -- someone expected to hit home runs instead of playing station-to-station -- Francoeur has a .344 slugging percentage. Last year, he had a .359 slugging percentage. And if the raw numbers don't drive home the point for you, keep in mind David Eckstein has a career slugging percentage of .361.

Look, no one doubts Francoeur's ability. He went in the first round of the 2002 draft for a reason and has already hit several towering home runs in his major-league career.

But at some point, that ability has to equal results, and now in the fifth year of his career, Francoeur has done nothing but move backward.

Time to cut him loose.

Scott Hairston, OF, Padres

Hairston always deserved more than he got.

What he got was banishment to the minor leagues by the Diamondbacks. They didn't like him at second base, his original position, but they never seemed interested in finding a more suitable position for him. So he just kept plugging away in the minor leagues, producing numbers like something out of a cartoon.

By the time he reached the majors for good, he was at an age (27) when most young players had already begun to break out. Seemingly overdue for his maturation, he had no choice but to accept a reserve role. Even after the Padres rescued him midway through the 2007 season, he still played the role of situational power hitter -- someone who could produce intriguing numbers for a part-timer but who remained just a part-timer.

Which brings us to now, his first shot as an everyday major-leaguer, which he only got by playing so well in a part-time role. The power is legitimate. He showed it last year with 17 homers in 326 at-bats. The batting average will likely fall a bit, but let's not forget he routinely hit over .300 in the minors. As for the stolen bases, shoot, the Padres know he can run now, and considering how much trouble they have scoring runs, they'll want to take advantage of it.

A 20-20 season seems like a legitimate possibility, and you'll take that even if Hairston can't maintain this batting average, right?

I wouldn't call him a must-start or even a definite breakout, but he deserves a roster spot, particularly in Rotisserie leagues.

Ian Stewart, 2B/3B/OF, Rockies

"Oh, yeah ... let's put Stewart at second base. That seems like a great idea."

Sure, it seems like a great idea. Clip-on ties, instant mashed potatoes and those sequels to The Matrix seemed like great ideas, but then they ended up hitting under .200 -- all of them.

I don't mean to blame the increased versatility for Stewart's struggles, but his added eligibility at second base certainly elevated him from "yeah, a pretty good sleeper" to "drop everything for him!" A potential 30-homer man at one of the weakest positions in Fantasy? It seemed too good to be true.

And it was, because it just isn't happening for Stewart this year.

He entered as a pinch hitter Tuesday and went 0-for-2, making him 0-for-3 in June after hitting .141 in May. The Rockies have started him only three times since May 19, and two of those starts came in an American League ballpark, where they could use the DH.

Clearly, new manager Jim Tracy doesn't put much emphasis on starting Stewart, and why should he? The guy's doing more harm than good right now.

So if he doesn't hit well enough to start, where does that leave him? He can either go to the bench, where talent goes to die, or he can go to the minors, where he can work to improve. Really, his final destination seems inevitable now. He just has too much growing left to do.

If you still have Stewart in a mixed league, you can stop dreaming. He won't improve without at-bats, and those at-bats won't come in the majors.

Nelson R. Cruz, OF, Rangers

Cruz belongs in textbooks as the perfect example of a Fantasy breakout. His numbers suddenly took off in the minor leagues last year, at age 27, and low and behold, they actually translated to the majors once he got regular playing time.

It's the kind of validation that stirs the pot of the wannabe scout in all of us.

Weeee! I can read numbers!

Well, let's just confirm the transformation as complete now, because we still had reason to doubt it before last week. I mean it -- we did. Going back to May 19, Cruz's batting average had dipped all the way to .265, he was striking out every day, and he had only one home run for the entire month. He looked like he might fizzle out like he had so many times before, causing him to get stuck in the minors in the first place.

But he didn't.

Instead, he hit seven home runs and stole five bases in the span of 11 games. He weathered his first real slump of the season and emerged more powerful, more dangerous and more indestructible than ever.

He's like Jason Voorhees, but he's not. He's Nelson Cruz.

And you know what? I'm fine with that. I now know Cruz will give me a 30-30 season -- or if not 30-30 exactly, some combination of 60 that you couldn't expect to get beyond the third round of any Fantasy draft.

Whether you start five outfielders or three, you should never bench him again. And if you look to trade him, aim big.

Hanging Sliders These guys look like Sliders, but not so fast! Their recent play might cause you to misinterpret their Fantasy appeal.

Luke Scott, OF, Orioles

Well, Scott did it. He gave everyone unreasonable expectations again.

This reminds me of the time he hit .336 with 10 home runs and a 1.047 OPS in 214 at-bats for Houston in 2006. Back then, you couldn't go anywhere without hearing the sleeper talk -- not even to sleep. As soon as you set your head on the pillow, your mind skipped to thoughts of him morphing into something that looked like the Shredder after he drank the mutagen at the end of Teenage Mutant Ninja Turtles II: The Secret of the Ooze, and you knew you had to have it.

But I saw Scott last week when he came off the DL and hit six home runs in four games. He didn't have the body type of Kevin Nash, and he didn't bury himself underneath a wooden dock.

Spoiler alert, I know.

Scott got hot, plain and simple. He has a history of blowing up for short stretches at a time before resuming his rightful place as a so-so power hitter. Just last June, he hit .333 with eight home runs and 1.093 OPS. Did you rush out and grab him then?

I don't mean to say you shouldn't grab him now. If you want to ride out this hot streak, I can't blame you. But you should know you're getting a short-term solution. The Orioles might not even start him against left-handed pitchers once he cools off.

As a probable 20-homer man, he remains a serviceable on-the-wire, off-the-wire type in mixed leagues -- nothing more.

Change-ups For every correct prediction, there is an equal and opposite incorrect prediction. At times, I have to "change up" some of my own just to save face.

Wandy Rodriguez, SP, Astros

Yeah, I know. How can I do an about-face on someone whose value remains the same? It blows my changed mind.

Well, I didn't want to go overboard. I still consider Rodriguez one of the top breakout pitchers in Fantasy this season. I still see him as a guy you'll want to start almost always. But I made the mistake of saying he now pitches as well on the road as he does at home, and I don't feel comfortable with that way of thinking anymore.

He got bombed twice last week, which you could excuse as simple regression to the mean if both of those starts didn't happen to come on the road. I wouldn't go so far as to call him a must-sit on the road now, but I'd only call him a must-start at home.

And he should pitch fine at home even if he continues to flop on the road. He had a 2.99 ERA there last year.

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