Howlett damaged a shoulder in the act of reaching for the line to score a try last weekend against Glasgow Warriors. He sat out Tuesday's session in Musgrave Park before finally accepting today that he wouldn't make the starting line.
Back into the side however come internationals Conor Murray, Peter O'Mahony and Donnacha Ryan who was also mentioned on Tuesday as a doubt forthe trip to The Stoop.
Like Murray and O'Mahony, Ryan hasn't kicked a ball in anger since the Italy encounter for which he was considered doubtful because of a shoulder/back injury that had been affecting him during the RBS.
Nevertheless he gets the nod over Donncha O'Callaghan to partner Paul O'Connell in the second row while Cathal Sheridan and Ivan Dineen both named among the replacements get a first taste of Heineken Cup fare.
In Howlett's absence, Paul O'Connell will wear the captain's armband.
Munster: F Jones; D Hurley, C Laulala, J Downey, S Zebo; R O'Gara, C Murray; D Kilcoyne , M Sherry BJ Botha; D Ryan, P O'Connell capt; P O'Mahony, T O'Donnell , J Coughlan. Replacements: D Varley W du Preez, S Archer, Donncha O'Callaghan, P Butler, C Sheridan, I Keatley, I Dineen.