Here's a look at the transactions this week that had the most important fantasy impact.
Grady Sizemore, CF - activated from the 15-day DL
Impact: Injuries have caused Sizemore to miss significant time the last three seasons, and his numbers have also taken a hit as a result. The Indians center fielder was once a five-category fantasy threat who could be counted on for at least a .270 average, 20 home runs, 75 RBI, 100 runs and 20 steals a season. Those days are long behind him, as his average has dipped drastically since 2008 and his running game has grinded to a halt. The power is still there, but he has a long way to go before he can once again be considered among the fantasy elite. Ezequiel Carrera manned center field in Sizemore's absence, and should still get some starts in the outfield over the final few weeks of the season.
Jason Kipnis, 2B - activated from the 15-day DL
Impact: Most young hitters experience growing pains before finally adjusting to major league pitching, but that has not been the case with Kipnis this season. The 24-year-old second baseman hit .279 with six home runs in just 18 games with the Indians before missing a few weeks with a strained hamstring. He's now back in action, though he'll be eased back into a regular role since he's not yet 100 percent. His power numbers in the minors have been solid but not great, so don't expect him to be able to sustain his impressive home run rate over the rest of the season.
Franklin Gutierrez, OF - placed on the 60-day DL (oblique)
Impact: Gutierrez's season is done after he suffered a severe oblique strain Sunday. The Mariners center fielder missed the first month and a half of the season with a stomach illness and ended up with some very unimpressive numbers over the course of the season. He finishes with a .224 average and just one home run and 19 RBI in 92 games, though he did provide his fantasy owners with 13 stolen bases. Trayvon Robinson and Michael Saunders will likely receive most of the playing time in center field the rest of the season.
Julio Teheran, RHP - recalled from Triple-A Gwinnett
Impact: Teheran dominated Triple-A hitters this season, as he went 15-3 with a 2.55 ERA and 122 strikeouts in 144.2 innings for Gwinnett. He should be part of Atlanta's rotation the rest of the season as the team tries to give its regular starters some rest heading into the playoffs. He's made two starts for the Braves this season and failed to pitch past the fifth inning in either start. Nevertheless, at just 20, he has nowhere to go but up.
Stephen Strasburg, RHP - activated from the 60-day DL
Impact: Strasburg was one of last season's top stories, but his season ended prematurely as he was shut down in August after blowing out his elbow and undergoing Tommy John surgery. His final numbers were still quite impressive: 5-3, 2.91 ERA and 92 strikeouts in 68 innings. The flame-thrower looked sharp in his return Tuesday against the Dodgers, as his fastball velocity was still in the mid-to-high 90s. The results were there as well. He pitched five scoreless innings before handing it over to the bullpen (which proceeded to give up seven runs over four innings in a 7-3 loss). He's just 23 and could be a future Cy Young winner if he stays healthy.
Chris Denorfia, RF - activated from the 15-day DL
Impact: Denorfia was on pace to set career highs in most offensive categories before a strained right hamstring caused him to miss all of August. The journeyman outfielder appeared in 99 games for the Padres last season, marking the first time in five major league seasons that he'd topped the 50-game mark. In 95 games before his injury this season, Denorfia was hitting .261 with five home runs, 18 RBI, 32 runs scored and 10 stolen bases. Those are hardly the numbers that fantasy championships are built upon, but they could still have value in deep NL-only leagues. He'll likely be part of a platoon in right field with Jeremy Hermida, and as the right-handed part of that platoon, his playing time should be limited.
Jimmy Rollins, SS - activated from the 15-day DL
Impact: The Phillies shortstop and leadoff hitter missed a couple of weeks with a strained right groin, but he is back in time to help the team in the final weeks before the playoffs. He's been putting up his usual numbers this year, hitting for a decent average, scoring a ton of runs and stealing a bunch of bases, and adding some power for good measure. He might get the occasional day off over the next few weeks as the team takes a cautious approach with him, but he's still worth activating in all fantasy league formats.
Ryan Ludwick, OF - activated from the 15-day DL
Impact: Ludwick's home runs and batting average have declined every season since 2008, causing his fantasy value to nosedive. He still has some value in deep NL-only leagues, but he's clearly no longer the player he once was. He was dealt from the Padres to the Pirates at the trading deadline and then landed on the DL with back spasms near the end of August. It would seem unlikely that he'll miraculously turn things around this late in the season, and the change of scenery hasn't seemed to make a difference for him thus far.
Jonathan Herrera, 2B - placed on the 60-day DL (finger)
Impact: Herrera's season ended early after he broke his right index finger while playing with his kids Sunday night. Despite receiving semi-regular playing time this season, his numbers have been of no help in the vast majority of fantasy leagues. In 104 games and more than 300 plate appearances, the second baseman has hit .242 with three home runs and just 14 (yes, that's right, 14) RBI. Those numbers might still be acceptable for a guy who steals bases, but Herrera's four stolen bases don't even come close to making his ugly numbers tolerable. Mark Ellis should receive regular at-bats as the Rockies second baseman, but his numbers have been almost equally bad.