ST. PETERSBURG -- The Indians made the expected move of signing veteran right-handed reliever Luis Vizcaino to a Major League contract and adding him to their bullpen Thursday.

What wasn't as expected was the corresponding roster move. Left-hander Jeremy Sowers was optioned to Triple-A Columbus, opening up a spot in the Indians' rotation for Sunday's game against the Rays at Tropicana Field.

Tribe manager Eric Wedge said the Indians were still in the process of determining who would get that start, but he made it clear it would not be left-hander Aaron Laffey, who was moved to the 'pen last week in a show of desperation. Wedge said Laffey isn't under consideration to move to the rotation in this "cycle," but that could change the next time through the rotation.

"There's still a chance he might end up back in the rotation," Wedge said of Laffey, "but until we get things settled in the bullpen, [Laffey will stay where he is]. Two of our last three wins, he's pitched out of the 'pen, and that's real."

As for who will start Sunday, somebody from Triple-A Columbus figures to get the call. The most obvious candidate is left-hander David Huff, the most promising arm on the Clippers. Huff last pitched Tuesday, getting the win over Lehigh Valley, so Sunday's start would come on his fifth day.

When asked about the 24-year-old Huff earlier this week, general manager Mark Shapiro said he was still a work in progress. But that was before Sowers served up three home runs to the White Sox and sealed his demotion.

"We need to see his fastball command get a little better and his secondary stuff a little sharper," Shapiro said of Huff. "He's certainly a consideration now. We just need to see him a little further along before we bring him up here."

Who else is available? Well, count out the Clippers' most veteran arms -- right-handers Tomo Ohka and Kirk Saarloos. They both threw at least five innings in Thursday's doubleheader, so they wouldn't have adequate rest in time for Sunday.

The only other options, then, are left-hander Zach Jackson (1-2, 5.84 ERA in five appearances, including two starts) and right-hander Jack Cassel (2-3, 7.52 ERA in six starts). Cassel, though, is scheduled to start Friday.

Jackson is on the club's 40-man roster and was in the big league bullpen at the outset of the season. If the Indians promoted Huff, they'd have to add him to the 40-man.

Sowers is in his final option year, and, in two starts, he didn't do much to prove he can stick in the Majors. He went 0-2 with a 12.00 ERA, giving up 12 runs on 14 hits in nine innings.

Wedge didn't sound overly confident in Sowers.

"It still comes back to fastball command," Wedge said. "You have to command the baseball to have success here in the big leagues. He has to be able to throw the baseball where he wants to."

Wedge said he's not sure what role he'll use Vizcaino in, because this is a bullpen without set roles at the moment. Vizcaino, 34, was cut loose by the Cubs after recording four scoreless relief appearances in April. He last pitched on April 21, and the Indians had him at Progressive Field this week to throw live batting practice sessions on the side.

Vizcaino owns a career Major League record of 34-27 with a 4.31 ERA in 532 career appearances over 11 seasons with the A's, Brewers, Diamondbacks, Yankees, White Sox, Rockies and Cubs.

While the Cubs are on the hook for the bulk of Vizcaino's $3.5 million contract, all the Indians have to pay is the prorated portion of the Major League minimum.

"We've seen him real good with Chicago and New York," Wedge said. "It makes sense for us to take a shot with him."