Of course, pitching well is the best revenge.
Appel (9-1, 2.37) also will get the chance to avenge his only loss of the season since he'll be the starter in Friday's game against Fresno State at 6 p.m.
"Mark is self-driven," said teammate Stephen Piscotty. "We don't have to say anything to him to get him going. If he pitches with a chip on his shoulder, all the better for us."
The Cardinal (38-16) is the top seed of the regional, with the Bulldogs (30-26) getting the No. 4 seed. WCC champion and No. 2 seed Pepperdine (34-21) meets No. 3 seed Michigan State (37-21) at 1 p.m. to open the tournament.
Appel, who was named a first team All-American by Collegiate Baseball on Thursday and earned first-team honors on the All-Pac-12 Conference squad along with Piscotty on Wednesday, was snubbed for Conference Pitcher of the Year honors. That award went to Oregon's Alex Keudell (10-4).
Appel, however, will get plenty of attention this weekend with the MLB First Year Player Draft on Monday. Scouts will be swarming the 16 regional sites for one final look.
Fresno State won the WAC tournament title by defeating Sacramento State, 4-3, in 13 innings. The Bulldogs won the national title in 2008, when they were also a No. 4 seed to begin.
"That's a real tough four seed," Stanford coach Mark Marquess said. "They've had an outstanding season. That's a strong opponent for us."
Fresno State handed Stanford its first loss of the season on March 2, scoring seven runs on eight hits in eight innings against Appel. Take that game away and Appel would be 9-0 with a 1.94 ERA.
"The team is focused," said Piscotty. "We all know what the goal is. Now that it's time to play, we're all engaged and ready to go. Coach is always stressing to us, 'What have you done for us lately?' And the answer is always nothing. You have to go out and perform."
There will be some connections between the two teams. Stanford senior pitcher Brian Busick was a high school teammate of Fresno State junior catcher Austin Wynns at Poway; Piscotty and Fresno State's Will Anderson played at rival high schools in Pleasanton; and Cardinal Brant Whiting and the Bulldogs' Christian Belleque both played high school ball in Fullerton.
The Bulldogs are just one of three teams in the regional who have won a national title. Stanford won back-to-back titles in 1987-88 and Pepperdine won it all in 1992.
"It's a strong field but I don't think there is a weak field," Marquess said. "All the teams are playing well at the right time. There were a lot of good teams left out."
Among those who will be spectators are Arizona State, Gonzaga and Texas.
Stanford is hosting an NCAA regional for the 15th time, and the first since 2008, during the Marquess era. The Cardinal was 55-12 in the previous 14 and advanced to 11 College World Series in Omaha.
"The reason we play is to get to the postseason," Piscotty said. "It's time for all the hard work to start paying off."
The Cardinal is 11-10 against the NCAA field, including series wins over Vanderbilt, Rice, UCLA and Fresno State.
The winner of the Stanford regional will be matched with the winner of the Tallahassee regional, hosted by Florida State, seeded third nationally. UCLA earned the overall No. 2 seed and Oregon is seeded fifth. Arizona is also hosting a regional.
Stanford ended the regular season with a 5-3 victory over visiting California last Sunday. Piscotty was the winning pitcher and Jake Stewart supplied the power with a three-run homer in the second inning.
"We wanted to get some momentum back and play the game the way we want to play," Stewart said. "The seniors were talking about how this is the first time they will play a regional at home. We'll go out there, be excited and play with energy."
The Cardinal ended the year by winning nine of its final 11 games, more than enough to warrant hosting.
Stanford finished tied for fourth place in the Pac-12, with Arizona State and Oregon State, a mere two games behind co-champs Arizona and UCLA and a game behind third-place Oregon.
The Cardinal never lost more than three in a row all season, something that can be attributed to different guys stepping up to fill in for injured and/or slumping players. Alex Blandino, Dominic Jose, Danny Diekroeger and Brett Michael Doran found themselves in the lineup.
"Those guys came in ready to play," Stewart said. "We didn't miss a beat because of them. It's great to have that kind of depth."
Piscotty (5-2) stepped into the starting rotation and finished up with five wins on the year and an ERA of 2.57.
"I've pitched all my life and it was cool to get a few starts here," he said. "I'm not thinking about it as a pro career. My whole approach is to throw strikes and make them drive in the runs because I'm not going to walk anyone. I'm happy to do whatever is asked and not think about it."
Appel enters the postseason as the Pac-12 leader in strikeouts with 116. Appel is a semifinalist for the Dick Howser Trophy and Golden Spikes Award, given to the nation's top player.
Piscotty hit .319 during the regular season with a the Pac-12's third-highest total in RBI with 54. He has started every game in his career at first, left, third base, pitcher or designated hitter and is a finalist for the Olerud Award, given to college baseball's top two-way player.
Both players are projected to be first-round picks on June 4, during the first round of the MLB Draft starting at 4 p.m. on MLB Network.
Austin Wilson, Brian Ragira, Alex Blandino and Eric Smith all were named All-Pac-12 honorable mention. Wilson and Ragira got it for the second straight year. Wilson is hitting .290 with nine homers and 46 RBI, while Ragira is batting .318 with 47 RBI. Both have started every game in right and at first, respectively.
Smith is the team's leading hitter at .329 after 45 regular-season starts at catcher. Blandino, the team's freshman third baseman, is hitting .289 with 35 RBI and seven homers.