D-backs No. 1 prospect Dansby Swanson, the No. 1 overall pick in the 2015 Draft, has been sidelined since suffering a concussion two weeks ago and continues to experience symptoms, according to MLB.com.

Swanson, Arizona's top selection in June, was hit in the face by a pitch two weeks ago during a simulated game for the D-backs in Arizona. The shortstop, currently ranked as MLB.com's No. 12 prospect, was hit in the right side of his mouth and needed 14 stitches.

"Every now and then, he'll have a little spell where he doesn't feel quite right," D-backs farm director Mike Bell told The Arizona Republic. "So that slows it down a little bit. I think we're almost there, but we're waiting for that one day where he's completely symptom-free."

Swanson, 21, has yet to make his Minor League debut after Arizona selected him out of Vanderbilt. The D-backs gave the Golden Spikes Award finalist a $6.5 million signing bonus July 17.

"I think at this point he's even frustrated," Bell said. "Just one little thing here or there that kind of creeps up where he might get a little light-headed or something."