Esmerling Vasquez became the 12th starting pitcher tried by the Twins this season, a number that still could grow during September auditions. The rotation's struggles in 2012 have frustrated Twins' leadership and the fan base.

Another thing it has done: made us think twice about all of those decent-to-pretty good starting pitchers Twins fans might have taken for granted in the preceding decade or so. Johan Santana was a bona fide ace for many seasons, and Francisco Liriano electrified everyone in 2006. These guys, though, provided rotation stability in many seasons -- often in unheralded fashion or even despite grumbles from fans:

• Brad Radke: His first-inning struggles drove Twins backers crazy. But during the team's return to winning ways from 2001 until his retirement in 2006, Radke was 70-55 with a 4.11 ERA, averaging 30 starts per season.

• Eric Milton: Won 28 games combined in 2001 and 2002 and was even an All-Star in 2001 before an injury-plagued 2003 season and an eventual trade to the Phillies after that season.

• Kyle Lohse: Won 45 games from 2002 to '05, starting an average of 32 games during that span. His 4.61 ERA during that stretch wasn't exactly stellar; compared with the 5.43 ERA posted by Twins starters this season (entering play Sunday), however, it looks far more decent.

• Rick Reed: Had ony one good season here, but it was prototypical mid-rotation stuff: 15-7 and a 3.78 ERA in 188 innings in 2002.

• Kenny Rogers: Remember how in Rogers' one season with the Twins (13 wins, 31 starts in 2003) he was their fifth starter? Those were the days.

• Carlos Silva: He gave up what seemed like a million hits, but he also ate innings and gave the Twins a chance to win in a lot of ballgames between 2004 and 2007. During that stretch, he was 47-45 with a 4.42 ERA while averaging 193 innings and 31 starts per season.

• Scott Baker: He had injury issues -- culminating in Tommy John elbow surgery this year -- so it can be easy to forget what Baker offers when healthy. From 2007 to 2011, he went 55-37 with a 3.98 ERA and averaged 7.4 strikeouts per nine innings. He made at least 21 starts each year, with a high of 33 in 2009.

• Kevin Slowey: Before he became one of the symbols of all that went wrong in 2011, Slowey had double-digit victories in each year from 2008 to 2010, earning 35 victories and posting a 4.36 ERA in 71 starts.

• Nick Blackburn: Much like Slowey, Blackburn at least looked to be a capable back-end rotation pitcher for years to come after posting double-digit wins every year from 2008 to '10. He was 11-11 in 2008 and again in 2009 with an ERA just above 4.00. In 2008, he pitched very well in a 1-0 Game 163 loss to the White Sox.

MICHAEL RAND