PHILADELPHIA (Ticker) -- Mike Lieberthal, who has made the transition from injured-plagued catcher to All-Star, has agreed to a three-year, $18.5 million contract extension with the Philadelphia Phillies.

Lieberthal will receive a $1 million signing bonus, $4.5 million next season, $6 million in 2001 and $7 million in 2002. The team also has a club option for a fourth season worth $7.25 million.

In the final year of a two-year, $3.4 million deal, Lieberthal already earned a $50,000 bonus this year for making the All-Star team. He can make another $50,000 if he wins the Silver Slugger award as the best offensive catcher in the league.

Details of the new deal were announced this afternoon at Veterans Stadium before tonight's 8-5 loss to the Los Angeles Dodgers in 10 innings.

"We're very pleased to get this deal done," general manager Ed Wade said. "Mike has had a tremendous season and has developed into one of the top catchers in the game."

The third-overall pick in 1990, Lieberthal, 27, finally has shaken off injuries and surfaced as a major league force. He is hitting .310 with 25 homers and a team-high 78 RBI after missing the final 10 weeks of the 1998 season with a pelvis injury.

Defensively, Lieberthal leads all National League catchers with a .999 fielding percentage, having committed just one error in 715 chances. His 84-game errorless streak is the longest in baseball among catchers.

"This is a great move for our organization," manager Terry Francona said. "Mike has worked extremely hard along with our coaches and invested so much time into becoming a frontline catcher. Now that he's here, it's great to know he's going to be here for a while."

Lieberthal has been on the disabled list four times since being drafted. He has injured himself in a variety of ways, including separating his left shoulder, hurting a wrist lifting weights and tearing a left knee ligament.

The California native never hit higher than .266 in his previous five seasons. His best year was 1997, when he batted .246 with 20 home runs and 77 RBI.

Today's deal continues a trend for the Phillies. Since the spring of 1998, they have signed Lieberthal, third baseman Scott Rolen and center fielder Doug Glanville to multi-year deals. On Wednesday, first baseman Rico Brogna inked a one-year, $4.2 million extension.

"Mike is a prime example of what we've been trying to do here," Wade said. "We made a committment a couple of years ago to build around our young nucleus. Our No. 1 goal is to win. Our next important goal is to retain our young talent. I think this is a clear sign we're going to do that."

In other moves, the Phillies activated righthander Steve Montgomery from the 15-day disabled list and designated lefthander Jim Poole for assignment.

Montgomery has not pitched since August 3 due to a strained right groin muscle and is 1-4 with a 3.15 ERA in 35 games. Poole is 1-1 with a 4.33 ERA in 51 appearances.