NEW YORK — Howie Kendrick's sore left side had not improved, and it bothered the veteran outfielder to the point that the Phillies placed him on the disabled list an hour before Tuesday night's game.

The Phillies replaced him with a reliever, Mark Leiter Jr., a 22nd-round pick from NJIT.

Kendrick, the team said, suffered a right abdominal strain. He will be eligible to return from the 10-day disabled list on April 26.

"It's not his oblique," Phillies manager Pete Mackanin said, before the transaction. "It's something in his chest, when he threw. He told me if he were young and eager, he probably would tell everybody he could play. But he's a little smarter now and he's being cautious. I told him we're going to be cautious with it."

The Phillies were swayed, somewhat, by the fact that the disabled list no longer requires a minimum of 15 days. Kendrick, if he is activated when eligible, would miss just eight games because of days off in the schedule.

Kendrick was injured last Saturday when throwing.

Leiter's addition means the Phillies will play with an eight-man bullpen and four-man bench. Daniel Nava started in left field Tuesday. He could split time at the position with Aaron Altherr. The Phillies could swap a pitcher this week for outfielder Roman Quinn, if they feel shorthanded.

Leiter, 26, is the son of former Phillies pitcher Mark Leiter. If Leiter Jr. appears in a game with the Phillies, the pair would be the second father-son duo ever to play for the team, joining Ruben Amaro Sr. and Ruben Amaro Jr.

Leiter had struck out 11 and walked two in 5 1/3 innings with triple-A Lehigh Valley. He has experience as both a starter and reliever during his five seasons in the Phillies' minor-league system. He is the first NJIT product to reach the majors. The school, in Newark, N.J., has played baseball since 1949 and became a Division I school in 2006.