THE PHILLIES made the 1-year, $4.5 million contract with righthander Roberto Hernandez official yesterday. Hernandez will join a starting rotation with Cole Hamels, Cliff Lee and Kyle Kendrick.

In adding Hernandez to the 40-man roster, the Phillies had to subtract a player tabbed as the organization's top hitting prospect only 2 years ago.

Catcher Sebastian Valle was designated for assignment to make room for Hernandez.

Valle was rated the third-best prospect in the Phillies system by Baseball America in November 2011. But he was demoted to Double A Reading to begin 2013 and hit .203 with a .245 OBP and a career-low .603 OPS in 98 games.

"Prospects are prospects - sometimes they develop, sometimes they don't," general manager Ruben Amaro Jr. said. "He didn't develop at the rate we thought he would."

Valle, 23, signed as an amateur free agent out of Mexico in 2007, saw his stock rise after hitting .255 with 16 home runs and 74 RBI in 117 games with low-Class A Lakewood in 2010. In 2011, Valle's power dipped - he hit five home runs in 91 games at Class A Clearwater - but he hit .284 and represented the organization at the Futures Game, the annual top-prospect showcase held before the major league All-Star Game.

But Valle's stock dropped just as quickly in the last two seasons.

Valle hit .253 with 17 home runs in 105 games between Double A Reading and Triple A Lehigh Valley in 2012, but he also had a troublesome .271 OBP. Valle had 101 more strikeouts than walks (114-13).

After acquiring Tommy Joseph two summers ago in the Hunter Pence trade, and with Cameron Rupp developing quickly, the Phillies had a decision to make to solve the minor league catching logjam.

The Phillies brought back another former prospect to replace Valle on the catching depth chart. The team signed Lou Marson to a minor league contract with an invitation to spring training.

Marson was part of a four-player package sent to Cleveland in July 2009 in the trade that brought Cliff Lee to the Phillies. Marson, 27, known for his defense and game-calling, has hit .217 with a .602 OPS in 253 games with the Indians.

Marson missed most of the 2013 season with neck and shoulder injuries that stemmed from a home-plate collision in April. He would be the front-runner to share time at Triple A with Rupp, with recently signed Wil Nieves backing up Carlos Ruiz on the major league roster.

In addition to Marson, the Phillies also signed the following three players to minor league deals with invitations to spring training: outfielder Tony Gwynn Jr., outfielder Dave Sappelt and righthander Sean O'Sullivan.

Gwynn, 31, the son of the Hall of Famer with the same name, is a .244 hitter in seven major league seasons. He spent all of 2013 at Triple A Albuquerque (Dodgers), where he hit .300 in 104 games.

Enough starters

Ruben Amaro said he does not expect to make any more changes to the starting rotation with the addition of Roberto Hernandez.

Hernandez, 33, is expected to slide in after Kendrick, with Miguel Alfredo Gonzalez and Jonathan Pettibone competing for the fifth spot. Hernandez, previously known as Fausto Carmona, was 6-13 with a 4.89 ERA in 32 games (24 starts) with Tampa in 2013.

"He gave up a lot of home runs last year and we think thats atypical with what he does - he's more of a ground-ball guy," Amaro said. "We think that he's going to be better than that, particularly, and in the National League his numbers are excellent."

Hernandez was 3-1 with a 3.34 ERA in five starts against NL teams in 2013. He gave up 24 home runs in 151 innings (only 15 pitchers in the AL yielded more) but also had a 1.24 ground ball-fly ball ratio (seventh best in baseball among pitchers with at least 140 innings).

Phillers

The Phillies finalized their coaching staff by hiring John Mizerock as manager Ryne Sandberg's assistant hitting coach. Mizerock has previously worked on the coaching staff for the Kansas City Royals, most recently as the team's bullpen coach in 2008. He has spent the last three seasons at the Phillies' Class A affiliate in Clearwater, Fla. Mizerock replaces Wally Joyner, who took the hitting-coach job with Detroit . . .

Ruben Amaro said the Phillies are still talking to former manager Charlie Manuel about the possibility of joining the front office for 2014. Amaro said the role would be similar to Manuel's entrance into the Phillies organization in 2004, as a organizational hitting instructor and scout . . .

Righthander Shane Watson will have his pitching shoulder examined Jan. 6. Watson, the 40th overall selection (supplemental round) in the 2012 draft, was 4-6 with a 4.75 ERA in 16 starts for low-Class A Lakewood before being shut down in early July with shoulder pain. The exam will determine whether Watson will need surgery.

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