Jackson, 28, spent the 2011 season with the Chicago White Sox and St. Louis Cardinals. He posted a 12-9 record with a 3.79 ERA and a 1.44 WHIP in 31 starts.

In his nine-year career, in addition to the White Sox and Cardinals, Jackson has played for the Los Angeles Dodgers, Tampa Bay Rays, Detroit Tigers, and Arizona Diamondbacks. In 203 big-league appearances, he has a 60-60 record with a 4.46 ERA and 6.7 strikeouts per nine innings (K/9).

E-Jax will join any already stocked Nationals' rotation that includes Stephen Strasburg, Jordan Zimmermann, and recently acquired Gio Gonzalez. Ross Detwiler, Chien-Ming Wang, and John Lannan will audition for the final spot in the rotation, though Lannan is expected to be traded for a position player, preferably a center fielder. Last season, the average fastball velocity for Strasburg, Zimmermann, Gonzalez, and Jackson ranged between 92.5 mph to 95.8 mph (source: Fangraphs).

The 28-year-old right-hander had issues with control in the past, but has slowly improved his walk totals. In 2010, he walked 78 batters in 209 1/3 innings (3.4 BB/9) but lowered the number in 2011, allowing 62 walks in 199 2/3 innings (2.8 BB/9). 

Perhaps one of the biggest changes for Jackson was his pitch selection. Prior to 2010, Jackson relied heavily on his fastball, throwing it at least 65-percent of time (2003-2009). Starting in 2010, he started to mix in a lot more off-speed pitches, including a heavier dose of sliders and change-ups. In 2011, Jackson threw his slider 33.7% of the time, ranking him third among all major league pitchers with a minimum of 180 innings pitched. Throwing his slider generated a 51.7 swing percentage and a 15.4 swing-and-miss percentage, according to Texas Leaguers.

Overall, the Nationals get a reliable pitcher who can toss close to 200 innings and post average strikeout numbers. His control is questionable, but has improved over the past two seasons. On paper, E-Jax may not look spectacular, but his Fielding Independent Numbers (FIP) have improved over the past five seasons, posting a career best 3.55 FIP in 2011. I had Jackson worth between $14-$16 million per season based on projections, so the deal looks great for Washington.

From a fantasy standpoint, Jackson will likely post numbers close to his 2011 totals. He has an average number of strikeouts for a starting pitcher and has done a good job to improve his walk numbers. He'll be a low-tier starting pitching option for mixed league owners in 2012.