In one preseason lacrosse poll, the University of Maryland is ranked as high as fourth, although most polls have the Terrapins fifth or sixth. But if form follows this season, they probably will have difficulty winning two games in the Atlantic Coast Conference.

There are two reasons for the paradox. First, although an ACC champion is named, only four schools in the conference have varsity lacrosse programs. Second, those polls rank North Carolina third and Virginia seventh or eighth.

Maryland beat Duke in its opening game on Friday, 8-6, but the Terrapins will find out just how good they are during a midseason span that begins with a home game against the Tar Heels March 31, includes road games at Virginia and Navy and concludes with a home game against top-ranked Johns Hopkins April 20.

And in college lacrosse the rankings are everything. The eight teams selected for the NCAA postseason tournament are usually identical to the top eight ranked teams in the country. As usual, Johns Hopkins, Syracuse and North Carolina are considered the best in the nation.

Maryland's senior midfielder, Chris O'Brien, who is in the final stages of recuperation from hepatitis, and junior defenseman Dan Tracy are all-Americas. Second-year Coach Dick Edell's starting team likely will include as many as seven players who will be wearing Maryland jerseys for the first time.

Brian Willard, who Edell considers the best shooter on the team, will also be a major contributor. "Brian can score and score often," said Edell. "He's from one of the best high school programs in the country. He's got a hard shot and excellent shot placement."

Willard is a graduate of West Genesee High School in Syracuse, N.Y. The lacrosse players from that school are largely responsible for making Syracuse University a national power. The Orangemen probably had their toughest test yesterday, when they lost at Hopkins, 8-6, but a rematch in the NCAAs is possible.

At Navy, last season's starting attack unit (Tom Calabrese, Bill Dempsey and Ken McGann) has graduated. The three scored 48 of the team's 112 goals. To add punch to this year's attack, Coach Brian Matthews is moving second-team all-America Glen Miles from midfield to the front line. Last season, Miles got off 112 shots, scored 17 goals and had 13 assists.

Returning in the midfield are team captain Chris Adams and Jeff Bellistri, who scored 11 goals and had seven assists last year.

Virginia is led by honorable-mention all-Americas Roddy Marino and Jeff Nicklas. Both junior attackmen, Marino scored 21 goals and had 22 assists, and Nicklas scored 28 goals and 18 assists as the Cavaliers finished 10-3, 3-0 in the ACC.

Georgetown finished 4-9 last year, an improvement from its winless season of 1983, but Coach Bill Gorrow may have difficulty surpassing last season's record. With 20 new players on a 34-man roster, it was no surprise that the Hoyas dropped their first game to Holy Cross, 21-9.