Todd Walker is eligible at several positions and could be be an asset if Travis Buck falters in Oakland.

In fantasy baseball, one man's loss is always another man's gain.An injury to a player always provides an opportunity for someone else.This past week Tigers starting pitcher Kenny Rogers created a three-month hole in the rotation due to a blood clot in his throwing shoulder.The Tigers will go with veteran pitcher, Chad Durbin. If Durbin falters, however, the second option has huge upside.

Andrew Miller was projected as the first overall pick in the amateur draft before last season; he went to Detroit with the sixth pick partially due to his salary demands.Miller had three dominant seasons at North Carolina, and he has the stuff to be an ace with a mid-90s fastball from the left side and a big, sweeping breaking ball.Miller was guaranteed a September call-up in his contract last season, but he had trouble throwing strikes.As a result, the Tigers probably made the right choice by keeping him in the minors when they learned of Rogers' injury.Still, it would not be surprising if Miller gets his first opportunity in the majors by May.If he is able to harness his control, Miller has a chance to become the third young ace on Detroit's staff almost immediately.Certainly, he has the repertoire to be a big, left-handed strikeout pitcher a la C.C. Sabathia .

Even if Durbinis effective as the fifth starter in Rogers' absence, there's a chance Miller will see extended playing time with the team this season.Judging from his college career (27-9, 2.86 ERA, 325/140 K/BB in 309 innings), Miller has the ability to help AL-only fantasy owners in leagues with a deep bench would be well-served to carry him.

The purpose of this article in the coming weeks is not only to analyze those players that have received new opportunities on their respective teams but also those players that are in line for an increase in fantasy value. If all the stars align correctly, such is the case for Miller.Consider this list of "speculative players" as valuable wire fodder; one of these guys may be the addition that helps owners challenge for a league title.

HITTERS

Travis Buck, OF, Oakland: The A's purchased Buck's contract before Opening Day and with the spring injury to Dan Johnson will play him regularly in right field.The move was somewhat of a surprise considering how conservative Oakland is with their prospects, but it says volumes about what GM Billy Beane and company think of Buck.The 2005 first-rounder was in Double-A through last season, but has hit above .300 at every level in the minors. The Oakland prospect won't be much of a power threat– he has just 10 home runs in 497 career minor league at-bats – but he has a pure stroke and should develop more power as he matures.Buck offers average speed, but he should be able to transfer his 15 steals as a minor leaguer as well as his double-digit stolen base outputs during each of his collegiate seasons with Arizona State.While Buck's margin for error is small due to the A's numerous options, he compares offensively to a young Mark Kotsay and is a strong wire option for AL-only managers.

Kory Casto, OF, Washington: The injury to Nook Logan has provided an opportunity for Casto.Good riddance.A converted third baseman, Casto has been one of the top prospects in the Nationals' organization over the last three seasons.Admittedly, this isn't saying much in an organization with little quality minor league depth.Still, Casto has opportunity with his newfound role and could keep the job depending on his performance the next three weeks. While he has faced slightly younger competition the last two years, Casto has drawn at least 80 base-on-ballsin each of his minor league seasons, including 20 homers or more during that stretch. A quick start to his major league career could buy him as many as 500 at-bats, a .270 average and 15 home runs in RFK Stadium; which offers value to NL-only owners.

Alejandro De Aza, OF, Florida: De Aza certainly wasn't the frontrunner for Florida's center field job heading into Spring Training, but easily out-distanced veteran Alex Sanchez and young Eric Reed for the starting job. The 23-year old's track record in the minors is nothing to write home about, but his one attribute that will be attractive to fantasy owners is his 27 steals in less than 300 plate appearances in Double-A.De Aza has shown steady improvement in his stolen base rate, going from a 67 percent success rate in 2005 to 71% (at a higher level) last season.His .266 career average is concerning, but De Aza won't have any real pressure at the end of the Marlins batting order.He has an opportunity to succeed, and offers NL-only owners speed off the waiver wire. De Aza isn't the long-term answer in center field for Florida due to his lack of hitting skills, so managers should temper their optimism.

Elijah Dukes, OF, Tampa Bay: The knee injury to Greg Norton offered Dukes an opening day roster spot with Tampa. Since he is considered a prospect with a bright future, the team will attempt to keep him active with playing time and at-bats.When not having a run-in with his team or the law, Dukes has been a very productive minor league player.He nearly became a member of the 20/20 club while at Double-A in 2005, and he had 10 home runs and nine steals in only 283 at-bats last season while with Triple-A Durham.Perhaps even more impressive, Dukes improved what was once poor plate discipline. His near 1.0 BB/K ratio last season showed positive trends from previous campaigns. Dukes has also managed to average .284 over his career in the minors and is only 22-years-old.The worry here is opportunity, as the Devil Rays are already overloaded with young and talented outfielders.Everyday playing time would give Dukes the chance to challenge the 20/20 club and do so while hitting for average. Dukes' upside this season appears to be in the neighborhood of 300 at-bats barring multiple injuries in the D'Rays outfield.AL, NL and mixed league owners should be prepared to make a stand for Dukes should he become a regular on the lineup card.

Honorable Mention:

Todd Walker, 2B/1B/3B, Oakland: If the aforementioned Buck fails to impress early in Oakland, don't overlook Walker.The veteran can hit for average and his bat still has some juice.Walker is eligible at three infield positions under most format rules and giving the opportunity 300 at-bats this season isn't out of the question. In fact, his playing time and at bats could exceed expectations, especially dressing for a team that is loaded with players that are 'often injured.'