Xaverian's Nick Ahearn returns to a deep pitching staff for the No. 1 Hawks. (Debee Tlumacki / File photo for the Boston Globe)

By Zac Vierra, Globe Correspondent

With the baseball season beginning, the Globe's baseball Top 20 is largely based on how teams look on paper. Returning players and last season's success are the main reasons for the choices. But once teams get on the diamond and play a few games, the true top 20 will begin to form.

For now, Xaverian takes the top spot. Head coach Gerry Lambert has four pitchers returning that should play key roles. They include senior southpaw Tim Duggan, senior right-hander Nick Ahearn and junior righties Alex Person and Austin DeCarr. This deep pitching staff is a main reason why the Hawks are at the top spot.

Senior second baseman Chris Hoyt will leadoff for Xaverian and should be one of the best hitters in the lineup. Junior outfielder Aidan Desrosiers should also add some pop to the middle of the order.

BC High and St. John’s Prep come in at Nos. 2 and 3 and it wouldn’t be a surprise to see one of these teams at the top by the end of the season. The Catholic Conference will be tough as always.

BC High will be led by senior catcher Bob Melley who Lambert described as the best player in the Catholic Conference.

St. John’s Prep coach Pat Yanchus said pitching will also be the strength to his team. He will rely on junior RHP Dustin Hunt who transferred from Andover along with junior Brandon Bingeo who also plays shortstop. Senior outfielders Anthony Capuano and Andrew Donahue will return in the lineup for the Eagles.

Lowell is our No. 4 team. Again experience played a key role in this pick as the Red Raiders have 13 seniors this season and won the Merrimack Valley Conference two years in a row.

At No. 5 is the defending Division 1 South champions Franklin. They have four seniors that will play important roles. Catcher Reed Turgeon and shortstop Brendan Skidmore are both three-year starters, while pitchers Tyler Buck and Bobby Chaiton have pitched multiple innings in the past for head coach Dave Niro.

Plymouth North is the first Division 2 team and the defending state champions should be tough to beat. The Eagles have pitchers who have been on the mound in high pressure situations including Alex Rozak who won the state final last year and senior Cody Holmes who has saved seven tournament games in the last two years.

A couple teams to watch are Barnstable and Lynn Classical who come in at Nos. 10 and 12 respectively.

The Red Raiders went 10-6 last year and return all of their defensive starters.

Lynn Classical snuck into the tournament last year at 10-10 but made it to the Division 2 final, losing to North Andover. The Rams are only graduated their shortstop from last season and will have 10 seniors on the team.

One team to watch that didn’t make the Top 20 is North Reading. Head coach Frank Carey only has two seniors on the team but he likes what he sees from his squad this year. With more than 600 wins and a spot in the National High School Baseball Hall of Fame, Carey knows what he is talking about.

For now, these rankings are based on off-the-field observations. It will be interesting to see how the rankings shake up once teams get on the field for a few weeks.

See the Globe baseball Top 20.