A new wave of pitcher tryouts

Esmerling Vasquez
had a strong season
in Triple A.

It's September now, which means that major league teams can activate anybody on their 40-man roster.

For the Twins, it represents a chance to test still more starting rotation candidates.

One such candidate, Esmerling Vasquez, is apparently to get the start Sunday in place of the suspended Scott Diamond.

Vasquez had a stealth season in Rochester — 100 innings, 2.78 ERA, 93 strikeouts and 38 walks. The Twins picked him up at the tail end of the 2011 season when Arizona waived him, then outrighted him just before spring training to make space on the 40-man roster for Darin Mastroianni.

Vasquez spent much of three seasons working out of the Diamondbacks bullpen without notable success. He hadn't been used as a starter since 2008. But he got drafted into the rotation late in the Red Wings season this year, and thrived.

Also in the plans for the final month: P.J. Walters, who had a few strong early-summer starts with the Twins before his shoulder started barking. He'll get some starts as well.

One pitcher who might lose pitching opportunities for these tryouts is Diamond, who has worked 172 innings (majors and minors) this season. He had 162 innings in 2011; I doubt the Twins will want him going 190 or so. That might be two or three more starts.

The goal, as I've said before, is to identify, develop and protect the pieces of a good future rotation. In Diamond's case, the first two parts have been done this year; holding down his September innings figures to be the third part.

For everybody else in the mix — Vasquez and Walters, Cole DeVries and Liam Hendriks, Sam Deduno and Brian Duensing— it's still identify and develop. The Twins know a healthy Diamond is in their 2013 rotation, but he's the only one of whom that can be said.