FORT MYERS, Fla. – Jake Arrieta was confident when he signed with the Phillies that he would be ready for the start of the season and the pitcher's progress continues to trend in that direction.

Arrieta will make his Grapefruit League debut Thursday against the Tigers as long as everything goes well Tuesday in his throwing session. The pitcher said he would throw 60 to 70 pitches in Thursday's game at Spectrum Field. He threw 32 pitches Saturday in two innings of a simulated game. Thursday's start is eight days away from the regular season's second game, which would be Arrieta's turn in the rotation.

"Obviously, I haven't been in a game yet, but I'm a quick learner and I like my chances at getting ready," Arrieta said at his introductory news conference.

Mark Leiter Jr. hurt

Mark Leiter Jr. returned to Philadelphia on Monday to undergo testing after feeling discomfort in his right forearm. The righthander appeared to have a lock on one of the  eight relief roles.

Leiter had allowed two earned runs this spring in his first 9 1/3 innings before he allowed four runs Friday in the start he left with tightness in his forearm. His spot as a long reliever could be filled by Drew Hutchinson, who started Monday's 6-5 loss to Boston, or Jake Thompson, who appears to be transitioning from a starter to a reliever.

Phillies pitcher Mark Leiter, Jr., throwing a  warm-up pitch against the Toronto Blue Jays during a spring training game at in February.
YONG KIM / Staff Photographer
Phillies pitcher Mark Leiter, Jr., throwing a  warm-up pitch against the Toronto Blue Jays during a spring training game at in February.

Hutchinson, in camp on a minor-league deal, allowed one run Monday on three hits in five innings. He struck out three and walked one. Thompson is already on the 40-man roster and has allowed just two earned runs this spring in 10 1/3 innings with nine strikeouts and three walks.

"Thompson has shown us the ability to have a swing-and-miss slider and get it out of the zone and get swings and misses, which is a quality that we think plays well in a major-league bullpen," manager Gabe Kapler said.

Rangers claim Joseph

Tommy Joseph's Phillies career ended Monday, when he was claimed off waivers by the Texas Rangers.

The Phillies designated Joseph for assignment last week to clear a space on their 40-man roster for Jake Arrieta. He went to spring training without a role on the team after Rhys Hoskins emerged last season and the Phillies signed Carlos Santana this winter to play first base. Joseph's roster spot always seemed to be in jeopardy.

Joseph could find a place in the American League as a designated hitter. He hit 43 homers over the last two seasons with a .757 OPS. Joseph played some left field and third base this spring but will likely stay at first base.

Extra bases

Aaron Altherr hit a mammoth homer Monday off Chris Sale, but it was the previous three at-bats that Kapler wanted to magnify. Cesar Hernandez grinded out a long at-bat before striking out. Cesar Hernandez and Rhys Hoskins both worked walks before Altherr crushed the first pitch he saw. The batters, Kapler said, were able to wear out Sale before Altherr stepped in. "Altherr hitting a home run doesn't happen in a vacuum. It happens as a result of team baseball. No one in the regular season is going to remember Cesar's punch-out, but it was a huge at-bat."… Ben Lively will start Tuesday against Toronto at Spectrum Field.