One of the best position battles we'll monitor closely during training camp this season will be Arizona's backfield with Andre Ellington and rookie David Johnson, who was drafted in the third round Friday. The winner could be a quality Fantasy option.

And don't be surprised to see Johnson come out on top.

Ellington has plenty of upside, but he's had trouble staying healthy during his first two years in the NFL. He's coming off hernia surgery, which has limited him this offseason, and he also dealt with a foot injury in 2014 that still isn't 100 percent healed.

He also struggled with his production last year as a featured back with just 3.3 yards per carry. His final stats were 201 carries for 660 yards and three touchdowns and 46 catches for 395 yards and two touchdowns.

If healthy, Ellington could easily beat out Johnson, but Cardinals general manager views Johnson as a three-down back. Johnson (6-foot-1, 224 pounds) has size on Ellington (5-foot-9, 199 pounds) with a similar skill set.

Last year for Northern Iowa, Johnson had 287 carries for 1,553 yards and 17 touchdowns and eight games with at least 100 rushing yards. He also excelled as a receiver with more than 30 catches in each of his four seasons with the Panthers, and he had 536 receiving yards as a senior.

Johnson is going to make things tough on Ellington, especially if he remains limited with injuries heading into training camp. Ellington is no longer a must-own running back this season, and I might pass on him on Draft Day and take Johnson with a better value pick.

Johnson is a running back I plan to target in all leagues.