Every season Major League Baseball teams receive contributions from some likely and not-so-likely minor league sources. The 2008 season stands to be no different, although baseball fans are not likely to see as large an influx of immediate-impact talent as was seen last season with top prospects making their debuts, such as Ryan Braun, Dustin Pedroia, Daisuke Matsuzaka, Troy Tulowitzki and Hunter Pence.

Regardless, according to an article by Dave Studenmund in The Hardball Times Baseball Annual 2008 (If you haven't already ordered a copy, go do so), the average age of major league baseball players is taking a dip for the first time in about 40 years, which suggests teams are relying more heavily on younger players.

The big question heading into 2008 is: Which rookies will have the biggest impacts this season?

AMERICAN LEAGUE EAST

Baltimore Orioles

With the winter winding down, the Orioles have already cast off some key 2007 contributors, including ace pitcher Erik Bedard who technically has not been traded yet, key offensive cog Miguel Tejada and sometime-sparkplug Corey Patterson. Waiting in the wings to replace those players are left-handed starter Troy Patton, shortstop Luis Hernandez and centerfielder Adam Jones, who is rumored to be on the way from Seattle.

Troy Patton LHP
Born: 9/85
Drafted: 2004 9th round
2007 MLB: 12.2 IP | 3.55 ERA | 7.11 H/9 | 2.84 BB/9 | 5.68 K/9

Patton was obtained from the Houston Astros in the Tejada trade this past winter. He doesn’t project to be an ace like the man he is more or less replacing, but Patton has the ceiling of a No. 3 – possibly a No. 2 – starter. Although Patton faired well in 12.2 innings with Houston in 2007, some of his career numbers suggest that 2008 might be a bumpy time for the young hurler. In each of his last three promotions – from High-A ball to Triple-A – Patton’s strikeouts-per-nine-innings (K/9) ratio has dipped each time from 9.06 to 7.35 to 6.07 to 4.59. Over the span of a 200-inning season, using his Triple-A ratio, Patton would strike out only 111 batters. Add in the fact that he was a flyball pitcher in Triple-A (GB% = 39%) and the majors (GB% = 27%), and he had low BABIPs (Triple-A = .262, MLB = .194) and you have the potential for a combustible rookie season.

Luis Hernandez SS
Born: 6/84
Signed: undrafted free agent
2007 MLB: 69 AB | .290/.300/.362

The slick-fielding Hernandez was claimed off waivers by the Orioles from the Atlanta Braves previous to the 2007 season. He certainly won’t resemble Tejada with the bat but he should improve upon Tejada’s dwindling defensive prowess. Unfortunately, Hernandez’ defence is unlikely to make up for his lack of offensive talent. With a career minor league line of .250/.299/.325, the shortstop has a long way to go to be league average. The switch hitter also struggles when batting left-handed, which he will do the majority of the time, and managed only a .218 average in 261 Double-A at-bats in 2007.

Adam Jones CF
Born: 8/85
Drafted: 2003 1st round
2007 MLB: 65 AB | .246/.300/.400

Allegedly soon to be acquired as the centerpiece in the upcoming Erik Bedard deal, Jones (who is nine at-bats over technically being a rookie, but what the heck he's topical) will take over centerfield for departed free agent Patterson. A right-handed batter, Jones hit both right-handed (0.955 OPS) and left-handed pitchers (1.003 OPS) equally well in 2007 at the Triple-A level. His power is developing and the athletic Jones has taken well to the outfield after being drafted as a shortstop. The biggest weakness in his game, offensively, appears to be his plate discipline as he walked only 7.9 percent of the time, while striking out 25.2 percent of the time. He also had a high BABIP at .370. Jones should be able to duplicate or better Patterson’s 2007 line of .269/.304/.386 but he won’t be as explosive on the base paths.

Boston Red Sox

The powerhouse Boston Red Sox chose to stand pat – for the most part – during the off-season, making minor alterations rather than retooling altogether. The reason for that partially comes from the fact the club has a nice wave of young talent bubbling to the major league surface. 2007 AL Rookie of the Year Dustin Pedroia should be joined by fellow youngsters Jacoby Ellsbury and Clay Buchholz, as Boston commits regular playing time to a number of unproven , but talented, players.

Jacoby Ellsbury CF
Born: 9/83
Drafted: 2005 1st round
2007 MLB: 116 AB | .353/.394/.509

If you didn’t know the former first-round pick’s name before the 2007 season, you do now. Not only was Ellsbury a force to be reckon with as the season wore down but his name surfaced in every Johan Santana trade article written this past off-season. Ellsbury received regular playing time late in 2007 and hit .353/.394/.509 in 116 at-bats. He then parlayed that success into a .360/.429/.520 line, including .438/.500/.688 in the World Series, showing he is one young player that will not wilt under pressure. Ellsbury is easily a Rookie of the Year favorite due in equally parts to his natural talent and the knowledge of his own strengths and weaknesses. He is not a power hitter and Ellsbury accepts that. In his 33 major league trial, 52.5 percent of Ellsbury’s batted balls were groundballs, while only 28.7 were flyballs. That allowed him to hit the ball on the ground and use his speed, something a lot of young players are reluctant to do. In the future, a top of the lineup featuring Ellsbury and Pedroia could be a nightmare for opposing managers and pitchers.

Clay Buchholz RHP
Born: 8/84
Drafted: 2005 1st round
2007 MLB: 22.2 IP | 1.59 ERA | 5.56 H/9 | 3.97 BB/9 | 8.74 K/9

Buchholz obviously has a lot a talent. Not many young players throw a no-hitter in their second big league appearance, which is exactly what Buchholz did against Baltimore on Sept. 1, 2007. Buchholz has also posted stellar minor league numbers throughout his pro career since being drafted 42nd overall in 2005. He has averaged about 12 strikeouts per nine innings in his minor league career and walked fewer than three batters per nine innings, which is impressive for a power pitcher. In his brief major league trial, Buchholz also showed that he can induce both flyball and groundball outs with regularity, although he is traditionally more of a flyball pitcher. Of the rookie pitchers likely to be handed full-time gigs at the beginning of 2008, Buchholz appears set to have the most immediate success.

New York Yankees

Even more shocking than Boston committing regular playing time to a number of rookies is the perennially veteran-laden Yankees relying heavily on young players. The 2008 Yankees will very likely have two key contributors to the pitching staff who are also Rookie of the Year eligible: Ian Kennedy and Joba Chamberlain. Second-year player Philip Hughes has only 72.2 big league innings under his belt and will join the duo as a regular contributor to the pitching staff.

Joba Chamberlain
Born: 9/85
Drafted: 2006 1st round
2007 MLB: 24.0 IP | 0.38 ERA | 4.50 H/9 | 2.25 BB/9 | 12.27 K/9

Like Ellsbury in Boston, Chamberlain has already made a name for himself thanks to an impressive late-2007 performance, including a 0.38 ERA in 19 games. The 12 hits allowed and 34 strikeouts (12.75 K/9) in 24 innings are also impressive. The problem with projecting Chamberlain, though, is lack of a track record. The prospect was so impressive that he dominated at the major league level in his first pro season, which alone says something. And if you’ve watched him pitch, you know the ‘stuff’ is there. Two minor warning signs about Chamberlain: he was a flyball pitcher in the majors (at the rare times opponents managed to make contact against him) and the BABIP was very low at .246. That said, if Chamberlain remains in the bullpen this season, he could put up some ridiculous numbers similar to Brad Lidge in 2004 (minus the saves) and J.J. Putz in 2006 (again minus the saves thanks to the presence of Mariano Rivera).

Ian Kennedy
Born: 12/84
Drafted: 2006 1st round
2007 MLB: 19.0 IP | 1.89 ERA | 6.16 H/9 | 4.26 BB/9 | 7.11 K/9

Kennedy does not come anywhere close to having the stuff of Hughes or Chamberlain but he has the pedigree of being a top prospect coming out of both high school and college, and he has amazing pitching instincts and abilities rarely seen in young players. With an offensive as potent as the Yankees’, young players like Kennedy can get away with a little less than on other teams where one mistake can sink you. One of the things that is most worrisome about Kennedy is that he is not likely to strike out a ton of batters at the major league level and he is also an extreme flyball pitcher. Albeit in only 19 major league innings, batted balls against Kennedy went into the air 50.9 percent of the time and another 22.6 percent were line drives. The BABIP against Kennedy have always been on the low end, including .265 at Triple-A and .237 in the majors.

Tampa Bay Rays

With a plethora of young talent gushing through the pipelines in recent years the Rays appear set to hand a full-time job to only one rookie at the beginning of 2008: Evan Longoria. Don’t dismay though, others including shortstop Reid Brignac, outfielder Justin Ruggiano and starting pitcher Wade Davis could appear before the All-Star break.

Evan Longoria
Born: 10/85
Drafted: 2006 1st round
2007 MLB: Did not play

The third overall pick in 2006 has a wide-open shot at the third base job for the Rays in 2008. However there are two warning signs for Longoria: He has only 104 at-bats above Double-A and he has always posted relatively high BABIP numbers, including .344 in 381 Double-A at-bats last year. Regardless, Longoria has done nothing but hit well since joining the ranks of professional baseball players and there is no reason why his success should not continue at the major league level. His debut season should fall somewhere in between those of fellow rookie third basemen Alex Gordon and Ryan Zimmerman.

Toronto Blue Jays

The Toronto Blue Jays do not appear as though they will be relying on any rookies at the beginning of 2008 and there do not seem to be many young players waiting in the wings for full-time assignments. The club’s best prospect Travis Snider is about two years away from joining the big league outfield.

Next up: American League Central