Denver Broncos running back Montee Ball underwent an appendectomy Monday but is expected to be ready for the regular-season opener against the Indianapolis Colts, according to ESPN.

Ball is the projected starter this season, but Ronnie Hillman took most of the first-team reps in practice Monday while Ball was out. C.J. Anderson also got some reps. Ball had two carries for eight yards in the Broncos' scrimmage on Saturday.

Ball moved into the starting role after Knowshon Moreno left for the Miami Dolphins as a free agent.

Ball rushed for 559 yards with four touchdowns last season as a rookie. He struggled early on by losing three fumbles in the first 10 games but settled down after that. He averaged 4.7 yards per carry.