There is a lot of mystery surrounding what the San Francisco 49ers will do with the second overall pick on Thursday. They could go defense or offense. General manager John Lynch is not letting anything leak from the 49ers' headquarters. Of course, there are still some gems to be found in later rounds.

Pro Football Focus did a special piece for ESPN that took a look at the best mid-round prospect fit for every NFL team in 2017 draft. For the 49ers, they identified a run stuffer to sit in the middle of the defensive line. That player is 6-foot-1, 331-pound defensive tackle Stevie Tu'ikolovatu out of USC. While Tu'ikolovatu's four sacks over the past three seasons don't scare any offense, he was dominant against the run and occupying gaps.

Pro Football Focus had the following to say about Tu'ikolovatu:

"Tu'ikolovatu will never scare teams with his pass rushing ability, but he is a dominant force inside who was nearly impossible for one blocker to hold up against at USC. His 91.7 PFF run-defense grade was second-best in the country to Stanford's Solomon Thomas, and he also impressed throughout Senior Bowl week with his ability to consistently control the line of scrimmage. Without the ability to effectively threaten the passer, Tu'ikolovatu is certain to be available on Day 3 of the draft. However, his ability to dominate in the run game makes him an ideal selection considering San Francisco's 3-4 scheme and needs."

The negative is that Tu'ikolovatu, who had 28 reps during the bench press at the NFL Scouting Combine, will turn 26 years old in June. He started his college career at Utah in 2009. Tu'ikolovatu took two years off to go on a church mission trip to the Philippines. Upon returning, he missed the 2013 season with a foot injury.

Seeking more playing time, Tu'ikolovatu decided to transfer to USC for the 2016 season. "Tu'ikolovatu actually lived in his car near the USC campus last summer until he was cleared to receive housing benefits by the NCAA," reports Lance Zierlein of NFL Media. Zierlein projects that Tu'ikolovatu will be selected in rounds 4 or 5.

Our own analyst, Aaron Erickson, had the 49ers selecting Tu'ikolovatu in his mock draft on Tuesday. Erickson had the following to say about the defensive player:

"At 6'1", 331, he possesses naturally low pad level and his 33" arms allow him to gain inside hand placement against centers and guards, whose arms are generally in the 32"-33" range. While his conditioning was such that fast-paced NCAA offenses could get him fatigued and take advantage of his pad level raising once he was winded and his legs got tired, NFL offenses are not allowed to operate at the same pace as their collegiate counterparts. Taking Stevie off the field on passing downs would keep his legs fresh and allow him to do what he does best: dominate the A gaps and actively shed blocks to pursue and disrupt run plays."