Cleveland running back Jamal Lewis is quickly approaching two round milestones: 30 years of age and 10,000 career yards.

He won’t hit the big 3-0 until Aug. 26, when the self-described ‘‘gym junkie’’ will be preparing for his 10th season as a pro. Barring an injury, Lewis, who once gained 295 yards in a game, will become the NFL’s 24th 10,000-yard man sometime in the next few weeks.

The Browns wouldn’t mind if he got there sooner — like Sunday.

With running backs Jerome Harrison (hamstring) and Jason Wright (neck) nursing injuries, Lewis could be busier than usual when the Browns (4-6) host the Houston Texans (3-7). And that’s more than fine with Lewis, who is still looking for his first 100-yard game this season after rushing for 1,304 yards in 2007.

Whether on the practice field or in the stadium when the game lights are shining, Lewis craves being Cleveland’s workhorse.

‘‘I want every rep (repetition),’’ he said. ‘‘I want every rep. I want it. I want it. Things happen. I’ve got to be there to answer the bell, and I’ll be there.’’

There hasn’t been a time when he wasn’t.

Lewis enters this week’s game with 658 yards on 185 carries, a 3.6-yard-per-carry average — below his 4.3 career mark — that has some wondering if the 29-year-old has lost a step. He hasn’t been breaking off long runs the way he did a year ago, when he scored on TD runs of 66 and 31 yards. His longest scoring run this season is four yards.

However, Browns coach Romeo Crennel said that’s not all Lewis’ fault.

‘‘We haven’t blocked as efficiently as we need to, to help him,’’ he said. ‘‘Last year we were able to get him into the second level and he can have a break out run. He really hasn’t had those this year to get him over that century mark.’’