There are a number of different situations mound inconsistencies can come into play as a game variable. For younger pitchers there is rarely a bullpen mound that is the same as the game mound.  Normally starting little league pitchers warm up on the side down an outfield line without a mound at all.  Release points will differ when moving from a flat surface to a raised mound with a declining slope.  Pitchers should focus on finding game mound release points just as much as loosening their arm when throwing warm up pitches.

Normally when throwing a bullpen in practice you are going to start and finish the session without sharing the mound with another pitcher so you don't have to deal with other pitcher's foot holes, this is never the case in a game situation.   If you feel these holes are affecting pitch Lokation you must make an adjustment to overcome the situation instead of letting it become a mental block and loosing focus.

Adjustments include

• Fill in the hole between pitches so your foot is flat on the dirt.
• Make a bigger hole so you foot doesn't slide into another hole.
• Move to a different spot on the rubber.  
• DO NOT shorten or lengthen your stride

Other pitcher's foot holes in front of the rubber and in landing areas can affect 

• Balance, if half of your foot is in a hole and the other half is not. 
• Weight shift, if your foot is half on the rubber and half in a hole.
• Direction, if you move to a different spot on the rubber.
• Mental focus, if your too concerned with the mound.

Relief pitchers will have to pay special attention to game mound conditions because they are often the 4th, 5th, or 6th pitcher to throw on that mound.  Relievers also generally have less time to adjust to conditions when they enter the game because outings are much shorter than starters.  If you come in the game in relief make sure to inspect the surface for any holes you think might be a problem before you throw any warm up pitches.  There is no time limit for warm ups so don't rush through the allotted pitches, take your time and do some ground keeping if need be.

As pitchers get older, generally bullpen and game mounds are built with clay and have more stable surfaces, especially after high school.  But this general rule does not mean there will be no adjustment from the bullpen mound to the game mound.  Sometimes the home grounds crew will give the visitors bullpen a different slope on purpose to give the home team an advantage.  Other times the visitors pen is given the once over with a rake and called game ready.  Both instances will require a conscious effort to find a good release point during warm up pitches.