BOSTON -- One roster mystery has been solved, but the solution merely prompts another.

Yohan Pino, whose 1.92 ERA in 14 appearances (seven starts) for Class AAA Rochester leads the International League, will be promoted in the Twins in time to start Thursday's game in Target Field against the White Sox. Pino, a 30-year-old Venezuelan righthander who will be making his major-league debut, takes the place of Samuel Deduno, who is being returned to the bullpen for now.

"He's been pitching fantastic, along with three or four other guys down there," manager Ron Gardenhire said. "Throwing the ball very well, great ERA, the whole package. You could have had your choices down there and this is who [the front office] decided they want to give a shot to. We'll see how it goes. Exciting for him, first time in the big leagues. Pretty cool."

The Twins can move Mike Pelfrey to the 60-day disabled list in order to make room for Pino on the 40-man roster. Getting him on the 25-man active roster on Thursday will require another roster move, though -- and manager Ron Gardenhire offered no hints as to what that move might be.

Would they send Pedro Florimon back to Rochester? Gardenhire said he doesn't want to play with a short bench, as he is already while Eduardo Nunez tries to come back from a hamstring injury. Would they drop a reliever? The only relievers with ERAs above 4.00 are Jared Burton, who has pitched well in some critical situations lately, and Anthony Swarzak, a bullpen-saver who leads the Twins in relief innings pitched.

"A roster move will come accordingly on Thursday," Gardenhire said, "if everything goes according to plan."

The move didn't seem to come as a surprise to Deduno, who had given up 18 runs in 16 innings over his last four starts, a 10.13 ERA. "I'm a little disappointed a little bit because I wanted the ball again," said the Dominican righthander. "But I'm still happy because I'm still here. I want to make adjustments, because when I was in the bullpen I was doing well."

Meanwhile, the Twins face lefthander Jon Lester tonight, counting on their most effective pitcher, Phil Hughes, to break their three-game losing streak. The lineups:

TWINS

Santana SS

Dozier 2B

Mauer 1B

Willingham LF

Morales DH

Arcia RF

Suzuki C

Escobar 3B

Fuld CF

Hughes RHP

RED SOX

Holt CF

Bogaerts 3B

Pedroia 2B

Ortiz DH

Napoli 1B

Nava RF

Gomes LF

Drew SS

Ross C

Lester LHP