PHILADELPHIA (973espn.com) - The Eagles have made another significant undrafted free agent addition by signing former Oklahoma defensive tackle Charles Walker.

Once thought as a potential premium pick, Walker fell off the radar after leaving OU early to ostensibly prepare for the draft although it was later revealed that he was battling depression.

The 6-foot-2, 297-pound Walker then performed poorly at the NFL Scouting Combine, particularly in agility drills where he posted a 7.89 three-cone drill and 4.96 20-yard shuttle. As a comparison Eagles' sixth-round pick Elijah Qualls put up numbers of 7.65 and 4.66 in those the same activities. Qualls was also stronger with 33 reps at 225 compared to 25 for Walker and more explosive, flashing a 31.5-inch vertical to a 28 for the Oklahoma product.

The hope is Walker has overcome his issues and returns to the player Mel Kiper once described as a potential first-round pick.

The Eagles are searching for depth at defensive tackle behind starters Fletcher Cox and Tim Jernigan with run-stiffing nose tackle Beau Allen currently on the shelf with a torn pec. Second-year man Destiny Vaeao and Qualls are in the mix as well as Justin Hamilton, a futures signing earlier in the offseason.

Philadelphia's UDFA class, which will be announced officially sometime this week with rookie minicamp set to begin Friday, includes a number of players with draftable grades like West Virginia center Tyler Orlosky, Shepherd ultra-sized receiver Billy Brown, Houston quarterback Greg Ward and Wisconsin running back Corey Clement, a Glassboro native.

Brown will be moving to tight end at the NFL level while Ward will be playing WR.

Also being brought in are UCLA safety Randall Goforth, Ohio State punter Cameron Johnston, Indiana inside linebacker Marcus Oliver, Richmond defensive lineman Winston Craig, Brown’s teammate at Shepherd, safety Tre Sullivan, Virginia Tech quarterback Jerod Evans, Iowa State cornerback Jomal Wiltz and Walker.

-John McMullen covers the Eagles and the NFL for 973espn.com. You can reach him at jmcmullen44@gmail.com or on Twitter @JFMcMullen