Negotiations are on-going with a number of players, but Bower has announced that Adam Smith, Javan Vidal and Lee Knight have all been released from the club.
Experienced winger Smith joined the club in January 2018 and was formerly with Chesterfield, Alfreton Town, Gainsborough Trinity, York City, Mansfield, Town, Lincoln City, Halifax Town, Wrexham and Guiseley AFC where he played under Bower.
Versatile Vidal joined in the summer of 2017.
A Manchester City academy graduate, he re-joined Bower who signed him at Guiseley in 2016.
Vidal made just one first-team appearance at Premier League City, but spent time on loan at Grimsby Town, Aberdeen, Derby County and Chesterfield before he left in 2011.
Short stints with Greek club Panetolikos, Stockport County and Rochdale followed before he joined then-Conference North side Tamworth in 2014.
After a successful season, Vidal earned a move to National League side Wrexham, before joining Guiseley in the summer of 2016.
Having been released by League One side Oldham Athletic in the summer of 2017, Knight joined Avenue after impressing on trial.
Knight, who can operate either as a central striker or as a winger, spent the majority of the 2016/17 season on loan at Evo-Stik League Premier side Ashton United, before making a mark on Avenue fans when he rattled in a memorable goal in his first pre-season appearance away at Ossett Town.