Sierra High will have its hands full in its attempt to repeat as Sac-Joaquin Section Division IV softball champion.

So will Vista del Lago, the Timberwolves’ first-round opponent.

The two clubs go toe-to-toe next Thursday night for one of four opening-round contests at Arnaiz Softball Complex in Stockton starting at 5. The four winners advance to the double-elimination stage of the tournament, with the two quarterfinal games taking place immediately after the openers.

Sierra (14-4-1) is coming off a disappointing third-place run in the Valley Oak League, but the Timberwolves’ three conference defeats (two vs. Oakdale, one vs. Kimball) were each one-run losses decided by defensive miscues.

They need to be sharp behind Allison Walljasper, one of the section’s most dominant pitchers, against Sierra Valley Conference champion Vista del Lago (18-4), and the offense must find ways to plate runs when the opportunities present themselves.

The T’Wolves lack the offensive firepower of their 2011 team, but hard-hitting second baseman Sommer Wilson appears to have worked herself back into groove after missing the team’s first six nonleague games of the season while recovering from ACL tear.

The Eagles of Folsom are ranked 12th overall in the section by MaxPreps, one spot ahead of Sierra. They are anchored by pitching ace Olivia Brown (12-1, 1.97), senior C/2B Tayana Mata (.500, 4 HRs, 35 RBIs).

The VOL’s other postseason qualifiers are ranked in the top five in the section. Fourth-ranked Kimball (23-4) squares off with Los Banos (15-9-1), with the victor taking on the Vista-Sierra winner.

Oakdale (22-2-1), the VOL champion, is the top-seeded squad in the bracket and No. 2 in the MaxPreps section rankings. The Mustangs take on the winner of Monday’s outbracket game that pits Union Mine 11-5) and Central Catholic (12-12-1).

Western Athletic Conference titlist Ceres (16-7) takes on Cosumnes Oaks (19-6-1).