Louie Varland added more than a run to his Class AAA ERA on Thursday, from 4.30 to 5.31, by giving up six runs in three innings to Syracuse. It's not the type of performance that normally earns you a promotion to the major leagues.

But Varland will get that promotion Tuesday, and the righthander from North St. Paul will start at Target Field against the Rockies. He's sort of a human day off for the Twins starting rotation.

"A big part of it is, with 13 games in a row, [we're] giving our guys an extra day," Twins manager Rocco Baldelli said after Monday's 5-0 victory over Colorado. "We're not going to do that, obviously, every time around. … But we targeted this one as kind of a nice, ripe period of time in the middle of the season where we want to do it."

Getting another look at Varland is an added benefit. The righthander made the Twins' Opening Day roster by opening spring camp with four scoreless outings, though he gave up 14 runs over his final nine innings in Florida. Those problems carried over into the regular season, when he lost all four of his starts and gave up 17 earned runs in 16⅔ innings, a 9.18 ERA.

He was demoted to the Saints on April 22, and has been only marginally better there, going 2-5 while letting opposing hitters bat .273 off him.

"I'll tell you this: Lou's going to have to come up [and] use all his pitches. It's something he's been focusing on," Baldelli said. "He's been working on his offspeed pitches and how and when to use them. He's always been a guy with a really good fastball that he can use in different ways, but the pitching part of it is what he's focusing on."

To make room on the roster, the Twins optioned righthander Diego Castillo back to St. Paul, about 15 minutes after he pitched a scoreless ninth inning against the Rockies. Castillo gave up two runs in seven innings with the Twins the past two weeks, with seven walks and three strikeouts.