Your fantasy baseball cheat sheets are no longer of use. KFFL.com's Fantasy Baseball Diamond Market series gives you candid ratings of fantasy baseball players making MLB news in your rotisserie or head-to-head baseball league. If they're available in any of your fantasy baseball games as free agents, on waivers or for your FAAB dollars, you'll know whether they make the cut.

Key

Corner Infielders

Conor Jackson, Oakland Athletics

The A's made the decision to send struggling first baseman Daric Barton down to the farm Wednesday. Barton wasn't getting it done: He was hitting just .212 and hadn't homered yet. In his stead, Jackson should see the majority of work at first base, per Bob Melvin.

Luebke could be a sneaky addition

Jackson, who has outfield (and perhaps even third base) eligibility as well, also played under Melvin as a member of the Arizona Diamondbacks from his rookie year in 2005 to 2009. Co-Jax hit double digits in homers from '06 to '08, but since coming down with valley fever, which knocked out his 2009 campaign, he has been devoid of power.

Now that he appears to be back to full health and is seeing more consistent PT, Jackson is worth speculating on. The former Cal Golden Bear hovered around a .300 average during his best years in AZ, which gives us hope for decent BA help. Maybe a bit more power will follow, but don't bank on it; his fly-ball and ground-ball rates are headed in the wrong direction.

Shallow mixed: Pass

Deep mixed: Watch

AL-only: Acquire

Pitchers

Cory Luebke, San Diego Padres

The Friars had seen enough of Wade LeBlanc in their stable of starters, so they sent him back down to Triple-A Tucson Tuesday. Luebke, who will replace LeBlanc in the rotation, came on in relief Monday to strike out six in 3 1/3 innings, including five in a row at one point. His first start of the year will come against the Atlanta Braves this Sunday.

The Padres have all along had the intention of making Luebke a starter, and now he will get that chance after putting up a 3.23 ERA, a 1.00 WHIP, 43 strikeouts and 15 walks in 39 stanzas. Last year at Triple-A Portland, the 26-year-old southpaw registered a 5-0 record and a 2.97 ERA in 57 2/3 innings over nine starts. The lanky lefty's K/9 (9.92) and BB/9 (3.46), as well as some of his other peripherals, are in line for slight corrections with the transition to a starting role, but Luebke is now a valuable source of these stats, especially pitching at PETCO Park.

Shallow mixed: Watch

Deep mixed: Consider

NL-only: Acquire

Vance Worley, Philadelphia Phillies

After Worley's respectable start against the Seattle Mariners last Saturday (5 1/3 IP, 1 R, 2 BBs, 3 K's) Charlie Manuel chose to keep him in the rotation over Kyle Kendrick. Worley has performed admirably as a fill-in starter for the Phils; he's 2-1 with a 3.41 ERA and 22 punchouts in 29 innings pitched. The 23-year-old has allowed more than three earned runs in only one of his five starts, back on May 29 at the New York Mets.

The club sent him to the minors after his May 29 start to build up his arm strength and give him more confidence. Worley showed he was ready to come back up after going 2-0 with a 1.42 ERA and 21 K's in three starts with Triple-A Lehigh Valley. It's clear that Philadelphia has confidence in the righty, and with Joe Blanton's (elbow) rehab inching along, Worley could remain in the rotation through the summer months.

Shallow mixed: Pass

Deep mixed: Watch

NL-only: Acquire