Halladay goes through bullpen session

Philadelphia Phillies' Roy Halladay pitches during the second inning of a spring training exhibition baseball game against the Washington Nationals, Wednesday, March 6, 2013, in Clearwater, Fla. (AP Photo/Matt Slocum)

CLEARWATER, Fla. -- Roy Halladay, coming off the Tuesday Grapefruit League outing against Detroit that has raised concerns about the righthander, went through a coaching-intensive bullpen session Thursday at Bright House Field.

With periodic instruction from pitching coach Rich Dubee, Halladay threw 39 pitches -- 20 from the windup and 19 from the stretch -- with catching coach Mick Billmeyer squatting behind the plate.

Dubee assured reporters Wednesday that Halladay is "fine" after the righthander surrendered seven runs and walked four batters against the Tigers in his last outing. His fastball ranged from 84 to 88 m.p.h. in that outing with one scout estimating that he averaged about 85 m.p.h.

Except for the extra long conversations with Dubee at times, it appeared to be a typical bullpen session for the two-time Cy Young Award winner.

The best answers about Halladay's progress will come Sunday when he is scheduled to face the Baltimore Orioles in a home game.

In the event that something is seriously wrong with Halladay, the Phillies will have to either add an arm from the outside or rely on the rotation depth they have in the organization. Aaron Cook and Rodrigo Lopez, two of the veteran minor-league free agents the Phillies signed to be part of that depth, will throw Thursday against the Pittsburgh Pirates at Bright House Field.

Righthander Kyle Kendrick, the team's No. 4 starter, will pitch in a minor-league game at the Carpenter Complex.

The schedule had been set that way before Halladay's Tuesday start created concern.

The lineup against the Pirates:

Freddy Galvis, SS

Michael Young, 3B

Chase Utley, 2B

Ryan Howard, 1B

Dom Brown, RF

Darin Ruf, DH

Laynce Nix, LF

Erik Kratz, C

Ender Inciarte, CF

Aaron Cook, P