Here's a look at the transactions this week that had the most significant fantasy impact.
Brandon Inge, 3B - signed a one-year contract
Luke Hughes, IF - designated for assignment
Impact: Hughes' stay in Oakland didn't last long, as the A's found a new face to fill the third-base job. Hughes went just 1-for-13 in four games with Oakland after a 2-for-10 start with the Twins. Just days after being released by the Tigers, Inge was signed by Oakland to hopefully bring some stability to third base. That position has been a revolving door so far, as the A's gave Josh Donaldson, Eric Sogard and, most recently, Hughes a chance to earn the job full-time. Inge isn't likely to do much better than those players, as he's coming off a season where he hit just .197 with three home runs in 102 games and hasn't hit above .250 since 2006.
Cory Gearrin, RHP - optioned to Triple-A Gwinnett
Tim Hudson, RHP - activated from the 15-day DL
Impact: Gearrin failed to get into a game during his five days with the club after taking Jair Jurrjens' roster spot. Hudson missed the first month of the season recovering from offseason back surgery but pitched well enough in his return Sunday to pick up a win against the Pirates. In five innings, he gave up just two earned runs on six hits and two walks while striking out six batters. He's gone 33-19 the last two seasons with an ERA of 3.02 and should be activated on fantasy rosters immediately. He was on a strict pitch count in his first start back, but should gradually be stretched out over time.
Randy Wells, RHP - optioned to Triple-A Iowa
Ryan Dempster, RHP - activated from the 15-day DL
Impact: Wells has become less effective in each season since becoming a regular in the Cubs rotation in 2009. He started this year with two rough outings where he gave up a combined six earned runs, nine hits and a whopping nine walks in just 8.2 innings. He'll try to work through his issues with the Cubs' Triple-A affiliate in Iowa. Dempster looked sharp Thursday after missing a couple of weeks with a strained right quad. He pitched eight shutout innings against the Reds, giving up just three hits and one walk, while striking out six. He's clearly safe to activate on your fantasy roster.
Pablo Sandoval, 3B - placed on the 15-day DL (left hand)
Conor Gillaspie, IF - recalled from Triple-A Fresno
Impact: Sandoval is expected to miss four to six weeks after he broke the hamate bone in his left hand. He was one of the Giants' best hitters at the time of the injury, leading the team in both home runs (five) and RBI (15), while hitting .316. Gillaspie should get a good look at third base while Sandoval is out. He has shown an ability to hit for a decent average in the minor leagues, though his other numbers aren't likely to be of much use to a fantasy team.
Johnny Damon, OF - contract selected from Triple-A Columbus
Jose Lopez, IF - designated for assignment
Impact: After being signed to a minor league contract by the Tribe in mid-April, Damon was finally added to their roster on Tuesday. Although his offensive production has declined in recent years, the 38-year-old outfielder is not without fantasy value. Damon hit .261 with 16 home runs, 73 RBI and 19 stolen bases for Tampa Bay last season and had played in at least 140 games 16 consecutive seasons entering 2012. Shelley Duncan figures to lose the most playing time due to Damon's arrival but should still get some at-bats against lefties. He's hitting .250 with three home runs and nine RBI through Monday's game. Lopez hit just .190 (4-for-21) as a backup infielder for Cleveland this season and isn't likely to have fantasy value regardless of where he ends up.
Mike Carp, OF - activated from the 15-day DL
Miguel Olivo, C - placed on the 15-day DL (right groin)
Impact: Carp injured his shoulder during the season-opening series against the A's in Tokyo and finally returned to action Tuesday. He was pretty good offensively last season, providing some pop to a lineup that ranked dead last in baseball in runs scored. He hit .276 and slugged 12 home runs and drove in 46 runs in 79 games and was looking to see what he could do over a full major league season this year before his injury. Olivo led the M's in both home runs (19) and RBI (62) last season, while hitting just .224. Jesus Montero will be the regular catcher while Olivo recovers from a strained right groin. He's been serving as the team's primary designated hitter and has been one of their most productive hitters. John Jaso will receive extra at-bats as a result of Olivo's injury, though the mediocre career numbers and only 2-3 starts a week make him only worth a look in deeper leagues.
Ryan Zimmerman, 3B - placed on the 15-day DL (right shoulder)
Bryce Harper, OF - recalled from Triple-A Syracuse
Impact: It was an eventful day for the Nats last Saturday, as they lost their regular third baseman to injury and called up their top pick from the 2010 draft. Zimmerman has been a productive hitter over his major league career, coming into the 2012 season with a career average of .288, while clubbing at least 20 home runs in four of the last six seasons. An MRI revealed some inflammation, but no structural damage to his right shoulder, so he shouldn't miss too much time. Harper figures to see significant playing time in left field, at least until Michael Morse returns from his back injury next month. He could also see time in center as well. The 19-year-old rookie phenom hit a combined .297 with 17 home runs, 58 RBI and 26 stolen bases in 109 games between Single-A and Double-A and projects as a five-category threat down the road. He could be a top Rookie of the Year candidate this year if he sticks with the team and is obviously worth adding to most fantasy rosters.
Cory Luebke, LHP - placed on the 15-day DL (left elbow)
Jeff Suppan, RHP - contract purchased from Triple-A Tucson
Impact: The Padres hope that Luebke will only miss two starts as he recovers from a strained left elbow. The left-hander has followed his impressive 2011 performance with a good start this year. In five starts, he is 3-1 with a 2.61 ERA through 31 innings. Last season, he went 6-10 with a 3.29 ERA and 154 strikeouts in 139.2 innings. Suppan pitched well in his first major league start since 2010, blanking the Brewers through five innings on four hits and two walks. Suppan came into this season with a career 4.69 ERA, though he hasn't finished a season with an ERA below that mark since 2007 (coming in at 4.62). That combined with a career strikeout rate of just 4.96 K/9IP means that he is best avoided in most formats.
Evan Longoria, 3B - placed on the 15-day DL (left hamstring)
Will Rhymes, IF - contract selected from Triple-A Durham
Impact: The Rays will be without their star third baseman for six to eight weeks due to a partially torn left hamstring that he suffered while sliding into second base during Monday night's game against Seattle. Longoria has been one of baseball's most productive third basemen over his career, as he hit a combined 113 home runs and drove in 401 runs the last four seasons. Tampa Bay will have a hard time replacing his bat in their lineup, and Jeff Keppinger and Elliot Johnson figure to get most of the playing time at third base while Longoria is out. Neither player has a decent enough bat to make him worthy of mixed-league consideration, but both could be worth a look in AL-only leagues. Rhymes brings a career batting average of .283 into this season, but had a disappointing year with Detroit last year, batting just .235 (20-for-85). He could also be part of the mix at third base but will most likely spend most of his time on the bench.
Kevin Youkilis, 3B - placed on the 15-day DL (lower back)
Will Middlebrooks, 3B - recalled from Triple-A Pawtucket
Impact: Youk is no stranger to the disabled list, as he missed 102 games over the last two seasons. When healthy, he's one of the top fantasy options at third base, but his health severely limits his fantasy value. He'll now miss some time recovering from a strained lower back, giving the BoSox a chance to get a look at rookie Will Middlebrooks at the hot corner. Middlebrooks worked his way up from Single-A to Double-A, and finally to Triple-A last season, hitting a combined .285 with 23 home runs and 94 RBI between the three levels. He's just 23, so he'll likely need some time to adjust to major league pitching. He could still be worth a look in deeper leagues.