Five marquee players landed on the disabled list with a collection of ailments and their owners are waiting for good news regarding their return. Even if you don’t own one of these, they have proven in the past to be the type of player to turn a race around with a hot streak. Which of these players should we be most concerned about and which one is likely to return and make an immediate positive impact?

B.J. Upton (OF, TAM) returned to action Friday, activated from the DL following a lengthy minor-league rehab assignment. Upton has been sidelined with back soreness resulting from a mid-March Grapefruit League OF collision with teammate Desmond Jennings. It is unclear whether Upton's running game, a significant component of his value, will be limited by the injury.

Juan Cruz (RHP, PIT) saved consecutive games on Tuesday and Wednesday as the Pirates took two out of three games from the Diamondbacks. With closer Joel Hanrahan (RHP, PIT) out for a second game with a tight right hamstring, Cruz stepped in and fired his sixth straight scoreless outing to begin the season.

This NL Weekend Series Matchup column previews six three-game series and two four-game sets.

Rangers and Tigers get weekend sets going with a four-gamer beginning on Thursday

Mark Melancon (RHP, BOS) lived a nightmare against the Texas Rangers on Tuesday night, allowing a walk, a double, and three home runs without recording an out. For the season, Melancon has now allowed 11 ER in only two innings, for a 49.50 ERA. He has taken two losses and was removed from the set-up role in the season's first week. Melancon has options remaining, and on Wednesday he was sent to AAA-Pawtucket in an effort to let him straighten out his mechanics and clear his head. How does his demotion affect the Red Sox pen?

After spending Opening Day on the bench, Juan Pierre (OF, PHI) has since started five of the six games in which the Phillies have faced a right-handed starting pitcher. Just two years ago, Pierre swiped 68 bases and had an SBO of 43%, though those numbers dipped dramatically last year. He was successful on just 27 of his 44 stolen base attempts (61%), and had a 27% SBO. It's unrealistic to expect a full rebound for Pierre, now 34 years old, but he could still be a strong speed source, and has already stolen two bases this year.

Matt Carpenter collected 7 hits and 7 RBI vs. the Cubs in three games this past weekend. He'll likely be on the bench when Lance Berkman returns Tuesday, but keep an eye on him ...

The Giants have been in this position before, but not quite for so long of a stretch: needing to find a fill-in for closer Brian Wilson, who is expected to miss the rest of the season. Late last season, Santiago Casilla answered the call, converting six of seven saves. But might the team do something different this time around?

This NL Midweek Series Matchup column previews seven three-game series and one four-game set.

This AL Midweek Series Matchups column previews one two-game series in Boston, three three-game series and three four-game sets.