NFL Combine preview: Key medical evaluations

The annual NFL Scouting Combine puts prospects through a grueling job interview process that tests them physical and mentally. The combine can basically be broken down into four categories: medical evaluations, interview process, agility/positional drills and verified measurements. This year, 326 invited prospects will travel to Indianapolis for the Combine, to be held February 27 to March 5, representing 326 different situations and game tapes. Of the four categories of evaluations, the medical information is the most important step of the Combine. Much draft stock could ride on the medical evaluations of the following players: Josh Rosen, QB, UCLA One of the top quarterbacks and overall players in this class, Rosen missed eight combined games the past two seasons due to an injury to his throwing shoulder and multiple concussions. While not undersized, he doesn't have ideal body armor or athleticism to evade the rush. Nick Chubb, RB, Georgia Although he has stayed relatively healthy the past two seasons, Chubb suffered a gruesome knee injury as a sophomore, tearing the PCL, MCL and LCL (but not the ACL). Are there any long-term worries? Kerryon Johnson, RB, Auburn One of the toughest backs I've ever evaluated, Johnson competes with a high pain tolerance, but his list of career injuries is extensive, dating back to high school. Mark Walton, RB, Miami (Fla.) After an explosive start to the 2017 season, Walton was lost for the rest of the season after an injury to his right ankle that required surgery. The good news: He is almost fully recovered and expects to perform every drill at the Combine. Anthony Miller, WR, Memphis After a relatively healthy final few seasons for the Tigers, Miller suffered a right foot injury in the bowl game, missing the Senior Bowl. Some around the league have expressed concern about the severity, which could have an impact on his draft grade. Auden Tate, WR, Florida State Tate missed one game last season due to a dislocated AC joint in his left shoulder, but nagging injuries have been an issue dating to high school. His medicals will be important. Richie James, WR, Middle Tennessee After producing 108 catches as a freshman and 105 catches as a sophomore, James' junior campaign didn't go as planned due to a broken collarbone that prematurely ended his season. He has healed and plans to work out at the Combine. Christopher Herndon, TE, Miami (Fla.) Herndon was in the midst of a breakout senior season when he injured the MCL in his left knee, requiring surgery. There are concerns around the league about the long-term ramifications, making his Combine medical evaluation paramount to his draft grade. Connor Williams, OT, Texas Williams is an enigma as a prospect, producing first-round worthy tape in 2016, but his 2017 season was a roller coaster of uneven play and injury. He suffered a knee injury in September and opted for rest over surgery, returning briefly late in the season. Timon Parris, OT, Stony Brook Parris started 41 games at FCS-level Stony Brook and earned respect from scouts, but he missed the final five games of 2017 with a fractured fibula in his right leg. The injury also kept him sidelined for the Senior Bowl. Isaiah Wynn, OG, Georgia After a dominant week at the Senior Bowl, Wynn had surgery the following week to repair a torn labrum. He is a first-round caliber player and scouts will be eager to receive an update on his status. Frank Ragnow, C, Arkansas One of the top interior blockers in this draft class, Ragnow suffered a high ankle sprain in October that prematurely ended his Arkansas career. The injury kept him from participating at the Senior Bowl. Harold Landry, DE/OLB, Boston College A possible first-round pick if he declared last year, Landry returned for his senior season, but his sack production nose-dived from 16.5 in 2016 to only five this season. Nagging injuries, mainly a bum ankle, were the culprit. Josh Sweat, DE/OLB, Florida State Sweat should test off the charts, but the medicals might be more important. He suffered a dislocated kneecap and torn ACL in his left knee as a senior in high school, requiring immediate surgery and near amputation. Sweat also suffered a torn meniscus in that same knee as a sophomore. Kemoko Turay, DE/OLB, Rutgers A lean-muscled edge rusher, Turay combined for 12 tackles as a sophomore and junior as he battled back from two surgeries on his right shoulder. The Combine will help reveal if there are any long-term concerns. Nathan Shepherd, DT, Fort Hays State Shepherd was forced to exit Senior Bowl practices mid-week after breaking his hand. While not a major injury, NFL teams will be interested in an update. Trenton Thompson, DT, Georgia One of the more talented defensive linemen in this draft class, Thompson struggled to stay on the field in college due to a laundry list of injuries, most recently an MCL sprain in his right knee in October. Jack Cichy, LB, Wisconsin Injuries have made him a forgotten prospect in this class on a national level, but his tape showed a top-50 prospect when healthy. Unfortunately, he hasn't played in a game since October 2016, missing the second half of the 2016 season with a torn left pectoral and all of the 2017 season with a torn ACL. Shaun Dion Hamilton, LB, Alabama The past two seasons have started strong and ended poorly for Hamilton. He suffered a torn ACL in his right knee in December 2016 and then suffered a fractured kneecap to the same knee this past November, ending his career in Tuscaloosa. Skai Moore, LB, South Carolina Moore led the team in tackles in four of the last five seasons -- the one season he didn't (2016) was a medical redshirt year after he required fusion surgery to repair a herniated disk. He returned and played well as a senior, but are there any long-term worries? Andre Smith, LB, North Carolina After a productive sophomore season, Smith suffered a serious left knee injury in the second game of the 2017 season, ending his season. Despite the injury, he left school early so he must feel confident about the injury. Nick DeLuca, LB, North Dakota State Injuries have been an issue for DeLuca the past two seasons, missing most of 2016 after a torn labrum. He also suffered a partially torn meniscus and required surgery during his senior season. Jaire Alexander, CB, Louisville Despite being undersized, Alexander is a tough-as-nails competitor. He was able to start only five games in 2017, though, mostly due to a right knee sprain that was reinjured when he was rushed back too early. Alexander also broke a bone in his hand during practice. Parry Nickerson, CB, Tulane Nickerson has started 46 games the past four seasons, but he suffered a major left knee injury during his first season at Tulane, which required potentially career-ending surgery. Some around the league have expressed concern about his long-term outlook. Derwin James, S, Florida State James missed almost all of the 2016 season with a lateral meniscus tear in his left knee, showing rust upon his return in 2017. If scouts aren't worried about that knee, James might land in the top 10 picks of this draft. Marcell Harris, S, Florida Harris was expected to have a Marcus Maye senior season, but he suffered a torn Achilles tendon over the summer and missed the season. Instead of petitioning for a medical redshirt and sixth year of eligibility, he elected to go pro. Mason Rudolph, QB, Oklahoma State Playing in every game the past three seasons, durability isn't a major concern for Rudolph, but he did miss the Senior Bowl due to a left foot sprain during training. NFL teams will be interested in the updated prognosis of the injury.