SAN DIEGO -- In their continued effort to make rookie Matt Harvey as relaxed as possible, the Mets on Sunday reunited Harvey with his most frequent batterymate: Rob Johnson, who caught Harvey often during his four-month stint at Triple-A Buffalo.

"I want Matt to feel as comfortable as he can," said manager Terry Collins, who has paired Johnson with Harvey twice in three starts. "I thought Rob did a great job the first outing with him. I just thought it would be a good matchup for him to catch Matt today."

Collins said earlier this week that he also wants starting catcher Josh Thole to grow comfortable catching Harvey, which is why those two formed the battery for the rookie's second start. But as Harvey adjusts to the big leagues, the veteran Johnson can be a valuable crutch. Harvey has often cited Johnson as one of his biggest influences in the Minor Leagues.

Johan finishes rehab, set to return Saturday

SAN DIEGO -- His final test run now in the past, Johan Santana is ready to rejoin the Mets next Saturday at Citi Field.

Santana struck out three over three shutout innings Sunday for Class A Brooklyn before throwing three simulated innings in the bullpen to increase his total to 90 pitches. Barring a setback, he should come off the disabled list and start Saturday's game against the Braves.

Santana, who walked one batter and allowed one hit for the Cyclones, has been on the DL since July 21 with a sprained right ankle. Jeremy Hefner will move to the bullpen to make room for Santana in the rotation, with Elvin Ramirez the most likely candidate for Minor League demotion to clear a roster spot.

Santana is 6-7 with a 3.98 ERA in 19 starts. But he is 3-5 with a 6.54 ERA in eight starts since throwing the first no-hitter in franchise history June 1 against the Cardinals.

Mets suddenly struggling to find clutch hits

SAN DIEGO -- The Mets, individually, left 29 runners on base during Saturday's win over the Padres. Andres Torres stranded 11 by himself. The Mets also left 18 runners on base in Friday's loss, for a grand total of 47 in two days.

It has irritated them.

"We've left way too many guys on," manager Terry Collins said before Sunday's series finale. "We got to where we are in the season because we drive in some two-out runs, and in the last few games, we have not been doing that. That's not the kind of club we are. Because we don't hit a lot of home runs, we need to use our two-out singles to produce runs, and we haven't been doing it."

It has indeed been an aberrational run for the Mets, who, despite their recent struggles, rank 11th in baseball in batting average with runners in scoring position. With two outs and runners on either second or third base, the Mets have compiled a .277 average, tops in the league.

Though their recent struggles have hardly been due to a single culprit, Torres took the bulk of the heat on Saturday. But Torres, like most of his teammates, has at least been passable with runners in scoring position this season, hitting better in those situations (.263) than in all others (.224).

"Lately, I thought he's been swinging the bat a lot better," Collins said of Torres, who hit .435 in eight games prior to Saturday's 0-for-4. "[Saturday] was not an example of how he's been hitting the ball."

Worth noting

• Top prospect Zack Wheeler's scheduled debut with Triple-A Buffalo on Sunday was postponed due to rain. Wheeler will pitch Game 1 of a doubleheader Monday at Syracuse, with Jenrry Mejia starting Game 2.

• Manager Terry Collins said the Mets would ideally like to add a second left-handed pitcher to their bullpen in advance of next weekend's series against the Braves, now that Tim Byrdak is on the disabled list. The team recently promoted lefty Robert Carson to Buffalo, where he has been pitching well, though 39-year-old C.J. Nitkowski, who has not allowed a run over his first five appearances with Double-A Binghamton, could also be a candidate. Carson holds the edge because he is already on the 40-man roster.