One thing?s for sure about today?s St. John?s Prep-Lowell Division 1 North baseball semifinal showdown: Eagles coach Pat Yanchus isn?t predicting 20 more runs from his offense.The Prep won 20-2 over Beverly in the quarterfinal round to reach today?s game at Alumni Field in Lowell at 4 p.m.?That?s unusual,” Yanchus said of the offensive outburst against Beverly. “It?s like, when I pitch batting practice, I throw the same pitch five or six different times to the same batter and get five or six (results) – a popup, one ground ball, a home run, a line shot.” But against Beverly, everything clicked. However, as Yanchus noted, “You don?t put up 20 runs very often.”What the seventh-seeded Prep (17-5) will have when it takes the field today is a pitcher who went 7-1 during the regular season in Chris Carmain. Eagles fans might have more recent memories of his prowess at the plate: Carmain?s last hits have all been home runs. He went 1-for-4 with a two-run homer in a playoff-opening win over Lynn English, then hit three homers and drove in seven runs against Beverly.?He?s been hitting all year, but hit only two home runs during the season,” Yanchus said. The coach also said, “He got hit pretty hard (as a pitcher) by Lynn English, but we won.”Carmain has three pitches in his arsenal.?He has a very good changeup and a good fastball,” Yanchus said. “Those are probably his best (pitches). He has a curve; he mixes curveballs in, too.”Carmain?s only loss this year came against BC High. One of his wins was a shutout against Gloucester, which meets Lincoln-Sudbury in the other D1 North semifinal game today (also at Alumni Field, at 7 p.m.).Carmain and the Eagles will face a team that entered the tournament with a 10-10 record and the last seed. But, Yanchus said, these facts are deceiving. The Raiders received the final seed due to a coin flip. And, he said, “They lost a lot of close games. They?re a tough team. They?ve been playing very well.”Lowell ousted sixth-seeded Peabody in the second round and got some revenge against Acton-Boxborough in the quarterfinals, eliminating a Colonial team that dealt the Raiders a pair of one-run defeats in the regular season.?They?re on a hitting tear,” Yanchus said. “They?re a pretty good 10-10 team. They?re 13-10 now.”The Prep scouted the Raiders in their playoff win over Acton-Boxborough, and Yanchus said he thinks Lowell will have its best pitcher on the mound today. Depending on whether the Raiders start a righty or a lefty, Yanchus might tweak his lineup a little. Garrett Folger has been out for four games, and will be out today.?We?re trying different outfielders, and if it?s the right-handed pitcher we think, we?ll have Dylan Gonzalez, who hit a three-run home run against Beverly,” Yanchus said. “He?s been playing the outfield spot. Pretty much the rest of the lineup will be somewhat the same.”St. John?s has already improved upon last season?s playoff showing, when it went 1-1, losing to Westford Academy. Two years ago, the Eagles made it to the state final, and lost by one run.