It's hard to hold Adalberto Mejia's last big-league start against him, Paul Molitor said Monday, given that it came in the hot-and-humid frying pan of Wrigley Field least month. In a game in which three of his teammates had to leave due to excessive heat, Mejia lasted only four innings, giving up six hits and four runs.

"It was tough for him to step in there. We were in the middle of a really tough trip, facing a really hot team on a really hot day," Molitor said. I don't think he ever got on track and [showed] the things we heard he had improved on over a couple months at Triple-A."

Mejia gets another start tonight, but like last time, it's probably another one-day promotion. Molitor won't say that, however; the manager said those decisions will be made after the Twins see what he can do inside the climate-controlled Rogers Centre.

The Blue Jays completed a sweep of the Orioles on Sunday, and Mejia completed only three innings when he faced Toronto last season in Target Field. Then again, he owns a 3.32 ERA at Class AAA this season, even after allowing seven runs in his most recent start.

"We're hoping to see him trust his stuff in the zone, and not nitpick or try to strike everybody out all the time. Trust his defenders," Molitor said. "If he can learn to be more efficient, it'll go a long way, because last year he ran into pitch-count issues."

Ervin Santana is scheduled to rejoin the team and start Wednesday's game, so the Twins have six pitchers in the rotation right now. "Don't know what will happen," Molitor said, before hinting that a trade is in the works. "We know where we're at in this part of the season, so we'll wait and see. With six [starters], you have to think about how you want to go forward."

In other starting pitcher news, Molitor said the Twins have set a date for Michael Pineda's return to game action: Aug. 6 in the rookie-level Gulf Coast League, where he'll pitch three innings. Pineda has made substantial progress in his return from elbow surgery, and Molitor said the 6-foot-7 righthander looks impressive.

"I watched him pitch at home in a simulated [game]. He's a big man, and the ball comes out of his hand" quickly, Molitor said. "It looks really good, considering where he's at and what could be down the road. It's been steady progress for him."

Pineda, the former Yankee who signed a two-year contract with the Twins before the season, is still on track to make a couple of appearances for the Twins in September, the manager said.

Here are the lineups for the first game at Rogers Centre:

TWINS

Mauer 1B

Rosario LF

Escobar 3B

Dozier 2B

Morrison DH

Polanco SS

Kepler CF

Garver C

Grossman RF

Mejia LHP

BLUE JAYS

Grichuk CF

Gurriel SS

Smoak 1B

Hernandez LF

Solarte 3B

Morales DH

Travis 2B

Smith RF

Maile C

Santos RHP