First baseman Yonder Alonso from the University of Miami (Fla.), the seventh overall pick in the amateur draft, agreed to a contract with the Cincinnati Reds shortly before baseball's midnight deadline Friday.

The deal is a major-league contract believed to be worth $4.55 million. It extends through 2012.

"If it wasn't done, the reality is he would be a college senior, and this is the last big year with the leverage," Reds scouting director Chris Buckley said.

Several first-round picks from the 2008 Draft remained unsigned as the deadline approached. On Friday, the Orioles signed No. 4 pick Brian Matusz to a $3.47 million deal with a big league contract. The No. 6 pick, Buster Posey, also signed a big deal with the Giants believed to be worth more than $6 million.

By signing the 22-year-old Alonso to a Major League deal, the Reds have to place the first baseman on their 40-man roster. But that was a lesser concern for the club during negotiations.

"One, we think he'll be here quickly," Reds assistant GM Bob Miller told the team's website. "It's not like we're worried about the [Minor League] options. The other issue is we have a lot of free agents and have some room. If it would have been a really tight roster, it would have been much more difficult."