Pineda, who was sidelined with right knee tendinitis, will get the start for the Twins on Friday night against the Tigers in Detroit. He's 4-3 with a 5.34 ERA this season.
Smeltzer went 0-1 with a 3.65 ERA in two starts in Pineda's absence.
He pitched six scoreless innings in his debut, giving up just three hits while striking out seven in a no-decision to the Milwaukee Brewers. But he was ineffective Tuesday, giving up five runs, including four home runs, in a 5-2 loss to the Cleveland Indians.