Gio Gonzalez (3-3, 3.64)
Gonzalez is the epitome of the player that could be dominant once he put it all together. When he first came up to the majors in 2008 with the Oakland A's, he didn't throw very hard and his secondary pitches were not getting outs, and as a result he walked nearly 7 batters per 9 innings and allowed over 2 homers per 9 IP. However, the Athletics were patient with him and were greatly rewarded. He still wasn't good in 2009, but his walks and homers allowed started coming down, and he finally broke through in 2010, going 15-9 with a 3.23 ERA. His strikeouts also went down, but most importantly was that his walks were at a manageable 4.13 BB/9 and he posted an above-average home run rate.
He was able to keep up his success in 2011, and with the A's being the A's, they chose to cash in on their new star. The offseason prior to 2012 saw him get traded to the Washington Nationals for a haul that included pitcher Tommy Milone, catcher Derek Norris, and two other minor league pitchers (neither with the A's anymore). Gonzalez has kept up his level of success since joining the Nationals, which includes a 21-win season in his debut season last year in Washington.
Gonzalez does not allow many hits or homers, so beating him will likely involve drawing plenty of walks. He features a 2-seam fastball, a 4-seamer, a curveball, and a change-up. The 2-seamer and curve are his best pitches according to FanGraphs' pitch values, and his 4-seamer is average while the change-up is solidly below average.
Here is Gonzalez displaying his curveball to strike out Dan Uggla (click to play).
Kevin Correia (5-4, 4.09)
Correia has been struggling ever since April became May. Early on, he seemed like a great find for the Twins, but he has only one quality start since April 28th when he threw 8 shutout innings against the Rangers, and even then his quality start was achieved by doing the bare minimum (6 IP, 3 ER against Milwaukee on May 27th).
The two main culprits have been easy to find. Correia is allowing more hits and also more home runs. Whereas he threw 36 1/3 IP in April with allowing only 2 homers and a .252 batting average, we've seen him serve up 11 homers and a batting average significantly over .300 in 34 IP in May and June. Clearly his key to success today will be to keep the ball in the park and limit the hits, which may prove difficult as he always gives up a ton of contact.
Correia throws a cutter, 4-seam fastball, splitter, 2-seamer, and curveball. His 2-seamer is his best pitch, and all his other offerings are rated as below average.