The Wisconsin high school baseball season kicks off on March 31, opening day for regular season action under WIAA regulations. Over the next two weeks, leading up to opening day, we'll be publishing our team previews ahead of the 2026 spring season, touching on programs spanning all state classifications, counting down through the official Prep Baseball Wisconsin Preseason Power 25 Rankings.
Perennially, we've submitted a preseason questionnaire to high school head coaches across the entire state. Their responses have been flooding in and we're using the detailed insight they've provided in our team-by-team preseason analysis.

Our 2026 preseason coverage continues today.

High School: Kewaskum Indians
Preseason Rank: No. 20
Head Coach: Mike Heisdorf
WIAA Division: 2
Conferece: Glacier Trails
2025 Record (Finish): 23-6 (conference co-champions)
Key Players Lost: Andrew Reichert

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ROSTER PREVIEW

No. of Returning Players: 3
No. of Returning Pitchers: 3
Team Strengths: Returning pitching, experience.

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DATA CENTER

TEAM RANKS:

This data is sourced from the 2026 Wisconsin winter showcase circuit and select 2025 events, compiled by Prep Baseball. We took the top-three metrics recorded by players from each high school in the following categories. Here is how Kewaskum's top-three performers averaged across each category:

Category	Top-3 Avg.	State Rank	Out of
Avg. Exit Velocity	88.4 mph	T-No. 36	of 102
Max Exit Velocity	98.3 mph	T-No. 19	of 102
Bat Speed	71.9 mph	T-No. 20	of 102
Max FB Velocity	85.0 mph	T-No. 22	of 70

INDIVIDUAL DATA STAND-OUTS:

• Carter Unger (6-foot-2, 170 pounds)
  
  • Top-ranked pitcher in the state's sophomore class
  • max fastball: 87.0 mph (T-No. 4 in state's 2028 class)
  • FB spin: 2,346 rpm (No. 2 in state's 2028 class)
  • CB spin: 2,378 rpm (No. 10 in state's 2028 class)
• Kingston Grisolono (6-foot, 205 pounds)
  
  • Ranked No. 15 overall in state's junior class
  • max EV: 107.0 mph (T-No. 3 overall in Wisconsin, T-No. 2 in state's 2027 class)
  • avg EV: 97.8 mph (T-No. 8 overall in Wisconsin, No. 4 in state's 2027 class)
  • bat speed: 77.2 mph (No. 11 overall in Wisconsin, No. 8 in state's 2027 class)
  • max fastball: 89.0 mph (T-No. 1 in state's 2027 class among LHPs)
  • CB spin: 2,489 rpm (No. 12 in state's 2027 class)
  • 60-yd. dash: 6.83s (93rd state percentile)
  • vert. jump: 28.4 in (No. 17 overall in Wisconsin)
• Kyle Haim (5-foot-9, 148 pounds)
  
  • max fastball: 79.5 mph
  • CB spin: 2,272 rpm (80th state percentile)
• Liam Stoffel (5-foot-11, 167 pounds)
  
  • Ranked No. 121 overall in the state's senior class
  • rot. accel.: 18.0g (T-No. 20 in state's 2026 class)

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X-FACTOR

OF/LHP Kingston Grisolono (2027; Evansville commit) is set to be the catalyst on both sides of the ball for Kewaskum this spring. Fresh off taking home First Team All-State honors and an appearance with the Wisconsin Future Game team, Grisolono looks to take the next steps this Spring. In his sophomore season, the left-handed bat slashed .436/.530/.745, with a 1.276 OPS, three home runs, six doubles, one triple, 14 RBIs, 24 hits, and 11 walks. The left-hander also will look to play a pivotal role on the mound after tossing 22 innings, striking out 26, allowing four earned runs, and 16 walks. The strength continues to tick up the power and velocity on both sides of the ball. Keep an eye out for Grisolono to take a major step forward this spring. 

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IMPACT UNDERCLASSMEN

RHP/OF Carter Unger (2028; uncommitted) in his freshman year was near unhittable on the mound for Kewaskum, as he looks to step into a major role in his sophomore year campaign. As a freshman, he went 4-1, with one save, tossing 43 innings to a 0.98 ERA and 0.86 WHIP. The right-hander struck out 47, walking 15, and allowing six earned runs. A young, projectable arm, last sitting in the upper 80s, set to lead a strong set of returning arms. Now, Unger might see some time with the bat after playing in a limited number of at-bats last year. The outfielder struggled with the bat, looking to reduce the strikeouts this year, as he looks to find a place within the lineup every day. 

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TEAM OUTLOOK

Kewaskum enters 2026 with the kind of foundation that makes rival coaches uncomfortable: a pitching staff that is not only intact but returning its two most effective arms from a 23-6 campaign that ended with a shared conference title. Head coach Mike Heisdorf is direct about where this team's identity begins and calls it the team's strength. The numbers back that up. OF/LHP Kingston Grisolono (2027; Evansville) and RHP/SS Carter Unger (2028) combined to go 7-1 last season, and both figure prominently as projected starters again in 2026. Grisolono posted a 1.27 ERA across 22 innings with 26 strikeouts in 2025, adding a shutout to his ledger. Unger was arguably the team's most reliable arm, going 4-1 with a save and a complete game, compiling a 0.98 ERA over 43 innings while striking out 47 batters against just 15 walks, a performance that placed him squarely among the state's elite young pitchers. On the showcase circuit, Unger's fastball spin rate of 2,346 rpm ranks No. 11 overall in Wisconsin and No. 2 among 2028-class arms in the state, a number that helps explain why opposing hitters managed just a .144 batting average against him in 2025.

Grisolono is the program's most decorated returning player and one of the most complete two-way prospects in Division II. The 2025 conference player of the year and first-team all-district honoree hit .436 with a .745 slugging percentage, 24 hits, three home runs and 14 RBIs in 17 games. His 107.0 mph max exit velocity ranks tied for third overall in Wisconsin and his 77.2 mph bat speed sits 11th in the state regardless of class. He runs a 6.83-second 60-yard dash, placing him at the 93rd state percentile, and his 1.58-second 10-yard split is tied for 10th in Wisconsin. Heisdorf noted that Grisolono is a three-year starter, and the offensive production he brings as an outfielder will be critical as the program works to replace the bat of departed infielder Andrew Reichert, who hit .419 with 26 hits and 14 RBIs a season ago. SS/2B Liam Stoffel (2026; Wisconsin-Stevens Point) is the senior the Indians will lean on to help stabilize the lineup. A three-year starter headed to Stevens Point, Stoffel drew 14 walks last season and posted a .444 on-base percentage. Heisdorf said Stoffel "will be relied on heavily to get our team going," a role that aligns with his patience at the plate and his 87th-percentile rotational acceleration recorded on the showcase circuit.

Beyond the top of the order, Heisdorf is expecting a breakout from OF Alex Jacobson (2026), whose 2025 plate appearances were limited but whose presence in the projected starting nine signals expanded responsibility in his senior season. 1B/RHP Cole Loser (2027) is projected in both the rotation and the lineup, and the coach identified him as someone "who should contribute in a big way." Loser appeared in 10 games as a pitcher and 10 as a hitter in 2025, showing enough to earn a prominent role moving forward. 2B/RHP Kyle Haim (2027) steps into the primary catching duties, a position transition that will be worth monitoring early in the season. Haim posted a 2.02 ERA in 17.1 innings of work last year and carries an 80th-percentile curveball spin rate on the showcase circuit. 3B/RHP Landon Zak (2027) is another junior in the projected starting nine whose showcase exit velocity of 96.0 mph hints at offensive upside as he settles into a more defined role.

The area to watch most closely will be overall lineup depth. Heisdorf acknowledged that replacing some of last year's offensive production is the team's primary development challenge. With Reichert's .419 average and on-base consistency gone, the middle of the order will need contributions from multiple directions, and the emergence of underclassmen Unger and OF Levi Whitfield (2027) as impact players will factor into how quickly the offense finds its footing. Marquee matchups against Homestead, West Bend West, and West Bend East in April will offer an early barometer on where this group stands.

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BOTTOM LINE

A pitching staff anchored by Grisolono and Unger gives Kewaskum a legitimate path to a conference title and a deep postseason run in Division 2. If the lineup finds the production to replace Reichert's presence, the ceiling for this group is as high as any program in the region.

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Find more information on the 2026 Kewaskum program below:

+ 2026 Team Roster
+ 2026 Schedule
+ Visit the Prep Baseball Wisconsin Preseason Power 25 homepage

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POWER 25 COUNTDOWN