Andrew Miller (AP)

It has now been three starts in which Andrew Miller offered a glimpse of the kind of stuff that made the towering left-hander so intriguing in the first place.

Between his start on July 31 against the White Sox (during which the Sox acquired left-hander Erik Bedard, thus effectively turning Miller into a sixth starter) and his two most recent outings (last week against the Royals and on Thursday night, when he pumped zeroes for 6 1/3 innings in Texas against the Rangers), he has a 2-0 record, 2.08 ERA, 17 strikeouts and five walks in 17 1/3 innings. His fastball has been in the mid-90s, and he has featured a breaking ball capable of making a hitter like reigning AL MVP Josh Hamilton look foolish.

The 26-year-old has been featuring a lot of the same stuff that led to his call-up in the first place, when he dominated for Triple-A Pawtucket in June. In so doing, he has positioned himself as an intriguing option, both for the rest of the season and perhaps into the postseason.

Sox manager Terry Francona told reporters on Thursday that he had yet to make a determination about when Miller would next pitch or in what role, but certainly, Miller has solidified himself as no worse than a priority sixth starter option. In fact, his emergence is part of the reason why the Sox are comfortable having left-hander Felix Doubront (currently in Triple-A) prepare to pitch out of the bullpen for the rest of the year. Miller is viewed as a trustworthy starting option who has given the Sox enough depth to permit Doubront to work in relief.

Moreover, Miller’s mastery of Hamilton on Thursday (three strikeouts in as many at-bats) suggested plenty of potential as a left-handed reliever, given the pitcher’s length, unusual release point and stuff.

When Miller signed his minor league deal with the Sox, it was with the idea that he was entering into a partnership that was expected to be beneficial for both the team and pitcher for the long term. Initially, his minor league deal (which called for a major league salary of $1.2 million in 2011) included a $3 million team option for 2012 that would become guaranteed if any team grabbed Miller off of waivers.

The option could have deterred other clubs from claiming Miller should he prove unable to help the Red Sox pitching staff at the major league level. However, Major League Baseball — which had initially approved the clause — ended up objecting to it, and so, according to multiple sources familiar with the deal, the contract was reworked to remove the option.

That has not been a relevant consideration. Though he has endured struggles at times, Miller has been a valued contributor for the Sox, who are now 9-1 in his 10 starts. With the Sept. 1 major league roster expansion from 25 to as many as 40 players now in sight, there will be no need to send Miller to the minors for the remainder of the year.

Even so, Miller — as a player with three-plus years of service time — will remain under the contractual control of the Red Sox through 2014, so long as the team tenders the arbitration-eligible Miller a contract.

Whereas the Sox non-tendered Miller last winter in hopes of getting him to sign a minor league deal, based on his performance to date in 2011, it would seem a near certainty that they will tender a contract to a pitcher who has shown in stretches the possibility of being able to contribute meaningfully to a big league starting staff (albeit in an as-yet undefined role). To date, the partnership between the pitcher and the club has been everything for which both sides had hoped, suggesting that it is likely to continue beyond 2011.