Tuesday was a tough day for Vikings running backs.

After the team announced starting tight end Irv Smith Jr. would miss the preseason with a thumb injury, starting running back Dalvin Cook left the practice field with what appeared to be a hand injury. He returned for one team snap and then sat out the rest of Tuesday's practice at TCO Performance Center.

Later, his backup, Alexander Mattison, also appeared to injure a finger on a play. He, too, watched the rest of practice from the sideline.

And a third running back, Kene Nwangwu, suffered what coach Kevin O'Connell called a "soft-tissue, lower-leg injury" on Monday. Nwangwu sat out Monday and Tuesday.

"He should be day-to-day," O'Connell said. "Just being smart with it."

Safety Harrison Smith, cornerback Patrick Peterson and guard Jesse Davis were given Tuesday off as O'Connell continues to try and preserve his older veterans for the start of the regular season.