Realistically, of course, either one is a deserving choice to start. And the truth is, in a game that matters, Dickey's knuckleball is a potential problem if you don't have a catcher who can handle it. My bet is La Russa will use Dickey once Yadier Molina replaces Buster Posey behind the plate. (Update: Molina left on bereavement leave, so that means Carlos Ruiz will have to catch Dickey.) I'd also like to see La Russa use Cain and Dickey for two innings apiece, giving him flexibility to match up in the late innings or have extra arms available if the game goes extra innings.
Anyway, Justin Verlander versus Cain is still a pretty good matchup as far as starting pitchers go. If Verlander isn't the best pitcher in baseball right now, you have to fight pretty hard to make the argument for somebody else. Cain is a longtime workhorse who threw a perfect game and is having his best season. He's a worthy starter.
Compare that to some other matchups we've seen:
2006: Kenny Rogers versus Brad Penny. Rogers had a long and successful career and Penny had his moments, but not exactly a matchup for the ages. Penny was 10-2 at the break but ended up with an ERA over 4.00.
2003: Esteban Loaiza versus Jason Schmidt. Schmidt was terrific for a few years there, but Loaiza was a journeyman starter who had a career year in '03, winning 21 games (he was 11-5 with a 2.21 ERA at the break).
1993: Mark Langston versus Terry Mulholland. Langston was one of the more underrated pitchers of his generation, but Mulholland was a guy who finished 18 games under .500 for his career. He was 9-6 with a 2.72 ERA at the break that year.
1990: Bob Welch versus Jack Armstrong. Welch, OK ... a very good pitcher who would win 27 games that year (even if he didn't deserve the Cy Young Award). Armstrong was a guy in his first full season with the Reds, 11-3 with a 2.28 ERA at the break. He'd win just one game in the second half and be out of the Reds' rotation in the postseason. Not sure if he got hurt that year, but he did later tear his rotator cuff and won just 40 games in his career.
1963: Ken McBride versus Jim O'Toole. Who? McBride was 10-7 with a 2.85 ERA at the break for the Angels. He'd get injured and win just seven more games in his career. O'Toole was a solid lefty for a few years with the Reds and won 98 games in his career. Still, he was only 10-8 with a 3.72 ERA at the break. Seems like an odd choice.
1962: Dave Stenhouse versus Johnny Podres. In the last year where two All-Star Games were played (to help raise money for the players' pension fund), Stenhouse started the first game for the American League. He was a rookie right-hander for the Senators who had started just 11 games at the break, going 6-4 with a 3.03 ERA. He'd win just 16 games in his career, certainly making him the most anonymous All-Star starter ever.