Also see: Fantasy Baseball Diamond Market - Rising

Fantasy baseball waivers and discarded fantasy baseball players can make or break a season. You may have adjusted your fantasy baseball cheat sheets over and over during spring training. If your team remains the same after opening day, though, you will probably have trouble competing in your rotisserie baseball league.

When is it time to give up on your fantasy baseball sleepers? Which players are worth retaining? KFFL.com's Diamond Market series gives you the fantasy baseball tips and advice you need to sort through the masses quickly.

Key

Discard - Drop player (in most circumstances)

Stash - Hold player if roster space is available; consider dropping if trend continues

Hold - Do not drop player (in most circumstances)

Outfielders

Juan Rivera, Los Angeles Angels of Anaheim

Fantasy baseball owners have become quite discouraged the longer they go without seeing Rivera (hamstring) in the starting lineup. Hasty owners are bailing. Big mistake. An MRI revealed nothing beyond a strain, and the .309-16-53 hitter is expected back sometime this weekend.

Shallow mixed: Hold

Deep mixed: Hold

AL-only: Hold

Jose Guillen, Kansas City Royals

It's easy to get mixed up, but Guillen (knee) isn't in Grade 2, that's just the degree of the tear in his lateral collateral ligament. He also has a strained muscle behind his right knee and will miss six to eight weeks. In his last 24 games, he's hitting .195 with a single dinger. That's awful. Given the timeframe, don't be clingy.

Shallow mixed: Discard

Deep mixed: Discard

AL-only: Stash

Rick Ankiel, St. Louis Cardinals

Ankiel (shoulder) is the likeliest to lose PT now that the Cards have dealt for Matt Holliday. The left-handed hitter's shoulder isn't 100 percent, so that's not such a bad thing. Colby Rasmus could lose out if he continues to slump, but St. Louis would probably prefer not to stunt the growth of its former top prospect other than with occasional days off.

Shallow mixed: Discard

Deep mixed: Discard

NL-only: Hold

Starting pitcher

Joba Chamberlain, New York Yankees

More restrictions for Joba

The Joba Rules remain in effect: Manager Joe Girardi and general manager Brian Cashman acknowledged that Chamberlain's innings will be capped; the limitation will affect the right-hander's role as well as the club's rotation. He'll probably remain in the starting five for the rest of the regular season, but how deep will he go? The news probably makes him difficult to trade, so just be prepared to cope as season's end draws near.

Shallow mixed: Hold

Deep mixed: Hold

AL-only: Hold

Jordan Zimmermann, Washington Nationals

The club placed its blossoming rookie hurler on the disabled list for precautionary reasons, they say. Zimmermann (elbow) said he felt to make his next start, which would've come Thursday. Acting manager Jim Riggleman admitted they're just shutting him down for a couple of weeks and that if his club were contending, Zimmermann would take his turns. The cap is expected to be about 150 to 160 innings; he's at 91 1/3 now. A couple of weeks' rest should put him on track for that range, so lean toward holding the upside.

Shallow mixed: Discard

Deep mixed: Stash

NL-only: Hold

Relief pitcher

Manuel Corpas, Colorado Rockies

Corpas (elbow) is having surgery to remove bone chips from his right elbow after all. It's possible that he'll return in September. His fantasy value is pretty much null at this stage, and it won't improve much in 2009's final few weeks.

Shallow mixed: Discard

Deep mixed: Discard

NL-only: Stash

Also see: Fantasy Baseball Diamond Market - Rising