These days, it’s not enough for an athlete to study his opponent.

He’s got to figure out his followers, too.

That can be quite a challenge at times for Florida Marlins outfielder Logan Morrison, one of Major League Baseball’s more prolific, interactive and entertaining Twitter users (@LoMoMarlins). He has more than 70,000 followers, which equates to roughly a week’s worth of crowds at Sun Life Stadium in 2011.

“This one guy today, he literally made fun of me and told I was a piece of s---,” Morrison said before a late September contest. “Then he came back with, ‘Give me a Re-tweet.’ That’s just confusing to me. I don’t even know what that means.”

Athletes are still learning what it means to have knocked down the wall between themselves and the public, through the use of social media.

Every day, it seems, there are a few more athletes who dip their toes in the Twitter pool. In April of 2009, an internet developer named Chad Walter launched Tweeting-Athletes.com as a weekend project, meant to track athletes on Twitter. He found 40 or so accounts. Now, on a site, he has list of more than 5,000, divided into more than a dozen sports, from NFL to NHL to MMA, and he acknowledges that he’s still missing plenty.

One of his more recent additions is Miami Heat forward Udonis Haslem (@ThisIsUD), who had resisted joining the site for two years before finally relenting. On the day he did in mid-October, Heat teammate Dwyane Wade tweeted that Haslem’s life would be changed as he knew it.

“I see a use for it now,” Haslem says, referencing the ongoing NBA lockout. “I didn’t see a use for it before. Things being the way they are, it’s a good way to keep my fans, the people who support me in the loop to what’s going on. I can’t do that through basketball right now.”

In his first two weeks, Haslem tweeted just 25 times, mostly innocuously, resisting confrontation. He did lash out twice, at a follower — who was actually a fellow Florida Gator and long-time supporter — for telling players to accept the owners’ proposal in labor negotiations.

“That’s the reason I’ve stayed off it, because it’s not right to respond,” Haslem says. “They always tell you, if you see something negative, don’t respond, but that’s not in my nature. So that was part of the reason why it was hard for me to join. But I’ve learned that you can’t really respond to the guy who has three followers. You got to let them have that.”

In this case, the follower had 25. Haslem, by that time, already had more than 9,000.

Haslem has the benefit of following thousands of fellow athletes into the Twitter fray, so he can see what works, and what doesn’t.

Walter has seen a significant shift in a short time.

“In 2009, when athletes would get on, they had no filter,” Walter says. “Whatever came to their mind, they said. You had athletes like D Wade cursing, and using the F-word. You just don’t see a lot of that anymore. I think teams have gotten involved, giving advice.”

Teams have. Leagues have.

Certainly, agents and marketing advisors have.

Even so, there tends to be a learning curve, a period of trial and error for everyone.

It takes time for athletes to understand the size and diversity of the audience. It takes time for athletes to comprehend that not everyone who cheers you on the field or court cares about — or agrees with — anything else that you happen to do or say.

And it takes restraint not to retaliate, when some of those so-called fans aren’t shy about sharing their feelings.

“There’s positives and negatives, mostly positives,” says Arizona Cardinals kicker Jay Feely (@jayfeely), who has tweeted nearly 10,000 times and accrued more than 40,000 followers. “The good thing about it is that you don’t have to go through medium of traditional media. You can express yourself, get your message across, promote a foundation or a cause, increase your name recognition.”

“Way more pros than cons,” Morrison says. “Getting to know your fan base is a pro. Them getting to know you is a pro. Letting them know what is going on as far as with you, whether it’s injury, personal stuff, charity work, it’s a way to communicate. And I don’t need to call up the local news station to put on a camp, I can just do it on Twitter.”

But there are cons.