This seems to be Peter Siddle’s greatest strength in the eyes of his team mates. When asked about their bowling attack, Australian players refer to Johnson’s speed, Hilfenhaus’s swing, Clark’s control and Siddle’s ability to run in all day.
You don’t want bowlers to run in all day. You want them to take enough wickets that your team can have a bat.
You also want your bowlers to release the ball immediately after running in, preferably propelling it somewhere towards the stumps. Merely running in isn’t even half the job. The batting equivalent would be ‘he holds the bat in his hands’.