In gambling it doesn't have to be logical and this is quite a large spread which many probably avoid, in fact it's actually the biggest spread of tonight, no other team is being given a larget number than that for tonight's games, but here are some facts:
1) Jan Maehlen is injured and won't be playing for Pepperdine. Lrone Jackson is also out for Pepperdine along with other 2 players who are less valuable - Dane Suttle Jr and Moriba De Freitas.
2) Gonzaga has no injuries reported as far as I've checked.
3) Pepperdine lost their last game to Saint Mary's by 29 points. Saint Mary's is more or less as good as Gonzaga, as it is ranked #23 and Gonzaga is ranked #24.
4) Pepperdine did win the game before that (12/29) against San Francisco (#156). By looking at the stats I've noticed Corbin Moore scored 19 pts and Taylor Darby added 10 pts that night for Pepperdine. Moore played 35 minutes and Darby played 32 minutes. Obviously SF's defense isn't the same as Gonzaga so the fact they scored many points whilst they had to play for almost the entire game somehow makes it harder for them to score the same against Gonzaga.
5) The line also stands on 128 which is quite a low scoring, so the expectations is that Pepperdine won't score much assuming that Gonzaga is leading the game, so the SF scenario is less likely and the SM scenario where they lost by 29 points is more likely in my opinion.
6) Gonzaga plays at home, so it's another bonus for them.
I think picking Gonzaga minus 22.5 points spread is OK/GOOD bet for tonight based on all the above ... but again, it's not always logical in gambling and we never know how things could develop ... if you have any comments I'd be glad to hear.