He said he had still been able to name 12 players that make up close to a best possible line-up for Hawke's Bay, with bowler Joey Field the only other key piece missing.
Christian Leopard is a boost to Hawke's Bay having missed a fair portion of the representative season because of his Central Stags commitments.
Castle said the 23-year-old has fantastic leadership qualities too.
"Guys look to him to lift their performance as well."
Jayden Lennox will captain a team that Castle said is out to make amends after they unsuccessfully challenged Hamilton for the Hawke Cup last season.
Hawke's Bay were bowled out for 166 in the first innings at Galloway Park, before Hamilton made 452, to claim a first innings victory.
"We really struggled last year and it's something that guys don't forget," Castle said.
"They're really keen to at least put in a good performance."
Regardless of the result, this match will be Hawke's Bay's final fixture for the 2020/21 season, and Castle said his squad have built a nice platform going forward with plenty of depth in the players they can call upon.
Hawke's Bay have played Hamilton in five previous three-day games since 2001, winning one outright, losing three outright and losing one on first innings.
Including games against South Auckland, Waikato and Waikato Country back to 1932, Hawke's Bay have only taken one win in nine Hawke Cup fixtures; an outright victory by 123 runs that saw them take the cup from Hamilton in 2009.
Pay Excellence Hawke's Bay men's team to play Hamilton at Nelson Park March 12-14
Jayden Lennox (c) - Napier Tech
William Clark - Havelock North
Liam Dudding - Cornwall
Matt Edmondson - Napier Tech
Izaiah Lange - Napier Tech
Christian Leopard - Napier Tech
Brad Schmulian - Havelock North
Ben Stoyanoff - Taradale
Graeme Tryon - Cornwall
Todd Watson - Napier Tech
Jono Whitley - Havelock North
Bayley Wiggins - Cornwall