Ace LHP Scott Kazmir threw his final bullpen session Saturday, mixing in sliders for the first time and feeling good.

"I was letting it go," he said. "I was breaking off a slider and wasn't really held back at all. It felt great."

Kazmir threw 60 pitches in the 18-minute session at the Naimoli complex, mixing in 10-12 sliders and 10-12 changeups. The lefty, rehabbing a left elbow strain, said the next step is a live batting practice on Tuesday, likely at the Trop before the home opener against the Mariners.

From there, it's still up in the air. Kazmir said there's a chance his return could be accelerated (a second batting practice session could get cut out, for example) - but he reiterated on Saturday he's not ready to say that's going to happen. It will all depend on how he feels, he said, with the key being how he comes back after getting three outs and sitting down before getting back up in a game setting.

Kazmir will likely throw two innings in an extended spring game, where things can be controlled, and the plan has been for a possible return to the big leagues by the end of this month.

"We have a couple things that's in place right now that we can maybe cut out - or maybe it's a good idea to keep it in," Kazmir. "We're playing it all by ear."

Kazmir changed it up on Saturday, bringing his buddy's dog, "King," with him. King, whose white fur boasted a few brown spots, stayed at Kazmir's side as he walked to the back fields to play catch. Kazmir said he has a two-year-old dog just like King back in Houston.

"Parents would let him come live with me," Kazmir said with a grin.   

In other rehab news:

*INF Ben Zobrist worked out again Saturday at the minor league complex, and will visit Dr. Carlon on Monday to get further x-rays on his fractured left thumb. Zobrist has been limited since the injury, doing one-handed swings and throwing.

*LHP Kurt Birkins, who is also rehabbing from a left elbow injury, threw live batting practice on Saturday, throwing 42 pitches in a quick session. Afterwards, Birkins said he was pain-free and felt good, but his stamina still needs some work. Birkins said he'll likely do another live batting practice, probably on Tuesday when Kazmir throws.

-- JOE SMITH

joesmith@sptimes.com