The Padres recalled Knehr from Triple-A El Paso on Sunday.
San Diego is treating Sunday's series finale with the Diamondbacks as a bullpen game, so Knehr could be a candidate to cover multiple frames in relief behind opener Craig Stammen, who is unlikely to work more than 2-to-3 innings. If Knehr goes unused Sunday, he could stay with the Padres and make a spot start or work as a primary pitcher at some point during the team's three-game series in Colorado that begins Monday. The Padres will need to fill Yu Darvish's (back) turn in the rotation during that series after he was placed on the 10-day injured list Sunday.