When looking for future aces, Hiroki Kuroda will never get into the conversation. At age 38, it is safe to say Kuroda does not have a decade left to pitch. But he seems to be getting better with age. So far, he is 6-2, 1.99, 0.995 WHIP in 9 starts, giving the Yankees a dependable 1-2 punch with Sabathia. Kuroda is certainly one of the reasons the Yankees are competing at the level that they are right now.
What more can one say about the job Matt Harvey has done? On a team that seems to be going nowhere this season, Harvey has been the best pitcher in the National League, going 5-0, 1.55 with 68 Ks in 68 1/3 IP to go along with a league leading 0.723 WHIP and 4.5 hits per 9 IP. On a staff that went with Jonathon Niese as their opening day starter, it is a no-brainer to say that Harvey is the Mets ace right now.
After a couple of down seasons, Boston Red Sox RHP Clay Buchholz is back at the top of his game. Perhaps manager John Farrell (Buccholz and Jon Lester's old pitching coach) returning to the team has impacted the young starters, as Buchholz is 6-0, 1.78 in 9 starts with 69 Ks in 65 2/3 IP. Lester has pitched well also, but to this point, Clay has pitched even better than he did during his All Star season of 2010. While Buchholz and Lester make a solid 1-2, the one now starts with Buchholz.
The St Louis Cardinals lost Chris Carpenter for possibly the entire season making Adam Wainwright and his new contract the number one starter on the staff. That did not last long as the new Cardinals ace is Shelby Miller. Miller gave up a leadoff single in his start against the Colorado Rockies and retired the next 27 batters, finishing with 13 Ks. That was not an oversight. Miller is 5-2. .40 in 8 starts and has 57 Ks in 51 1/3 IP. His 266 ERA+ is tops in the NL and he also sports a WHIP of 0.877.
Price won the AL Cy Young last season, but he may have a co-ace in Tampa Bay. In fact, if Price is traded this offseason, it is safe to say that Matt Moore is ready to be the number one pitcher for the Rays. Moore leads all of baseball with his 8(-0) wins, has a 2.09 ERA and a just over 1 WHIP to go with his average of nearly a strikeout an inning.
Cleveland has over the last several seasons traded aces such as Sabathia and Cliff Lee and part of the reason manager Manny Acta got fired last year was the fact that there was nobody standing out in the Indians starting rotation. There was no pitcher that struck fear into the opposition, led by the total disaster that was Ubaldo Jimenez. Maybe the reuniting with former manager Terry Francona helped Justin Masterson become the force he has been this season. Masterson leads the AL with his 10 starts, 70 IP, 2 CGs and 2 shutouts. He is also 7-2, 2.83 with 71 Ks and a 1.129 WHIP.
The Chicago Cubs probably considered a healthy Matt Garza as their ace coming into the season. They signed Edwin Jackson to a 4 year contract to be a 1 or 2. Jeff Samardzija seemed to have the upper hand on leading the staff. Though Samardzija has not pitched poorly, LHP Travis Wood has taken over the lead of a staff that needed a leader. Wood has pitched about as well as Mets fans were hoping Niese pitched. Wood is 4-2, 2.24 in his 9 starts, pitching 60 1/3 IP and a 0.928 WHIP.
The Washington Nationals have the game's most hyped pitcher in Strasburg and the 3rd best pitcher in the NL in 2012 (in regards to Cy Young) votes Gio Gonzalez. While he is still considered a number 3, no Nationals pitcher has dominated as much as Jordan Zimmermann. After being somewhat held back in his first two full MLB seasons, Zimmermann has taken advantage of his opportunity to stay in games. With just 1 complete game coming into this season, Zimmermann has had 3 to this point, one of them a shutout. He is 7-2, 1.62 in his 9 starts and he has a WHIP of 0.87.
The Arizona Diamondbacks had a deep rotation coming into this season, led by Ian Kennedy, Trevor Cahill, Brandon McCarthy and Wade Miley. Patrick Corbin, a left hander looked at as a pitcher who could improve over time, has been the D'Backs best pitcher. He is 6-0, 1.52 in his 8 starts, pitching to a 1.069 WHIP.
The Mariners will allow no competition when it comes to the number one spot in their rotation as long as they have Hernandez. Of course, Hernandez is going nowhere soon, as he recently signed a lengthy extension. RHP Hisashi Iwakuma has looked as good as scouts said he could coming into this season. He proved himself as a viable starter in the second half of 2012, but he has taken it to another level this season. At 5-1, 1.84 in his 9 starts, his numbers are slightly better than King Felix. Felix is still the ace, but the Mariners may have a solid 1-2 punch, something they need to have a chance to compete in a tough AL West.
So, picture the AL All Stars featuring Buchholz, Moore, Masterson, Iwakuma and Kuroda, with just Buchholz (2010) with an All Star appearance. The NL should feature Harvey, Miller, Wood, Zimmermann and Corbin, assuming they continue to pitch on this level. Two NL pitchers may establish themselves as their respective team's number ones before the season ends. Miami's Jose Fernandez is just 20, but he has made his impact on a struggling Marlins team. He is 2-2, 3.48 in his 8 starts and has 44 Ks in 44 IP and his WHIP is 1.159. San Diego's Andrew Cashner has gotten into a grove after an offseason injury nearly ruined his season. Cashner has the best stuff of any Padres starter and has shown it to this point going 3-2, 3.02 in 11 games, 6 starts. Both Fernandez and Cashner could become aces by the end of the season.