SCOTTSDALE, Ariz. -- Caleb Smith felt good and thought his stuff was likewise in Sunday afternoon's 6-3 loss to the Giants.

Just not when he was pitching out of the stretch.

"Something just felt off out of the stretch today," Smith said. "Just wasn't able to command pitches out of the stretch."

The day started off well for Smith, as he struck out the first two batters he faced before allowing a pair of walks. Then in the second, after Brandon Crawford reached on a bunt single, Smith again lost a feel for the zone, walking the next two hitters.

Smith left the game with one out in the second because the team did not want him to throw too many pitches in any one inning. He was then reinserted to start the third and retired the Giants in order.

"I'm not worried," Smith said. "It's still Spring Training and there's a lot of time to fix it. And I just got to move forward."

Weaver working on back field

Finding innings for all the pitchers the D-backs are trying to stretch out as starters will continue to get more challenging now as pitchers work deeper into games.

"We've got 14 guys we're trying to stretch out," manager Torey Lovullo said. "We're trying to be as creative as possible."

That's one of the reasons Luke Weaver, who is expected to be in the Opening Day rotation, will pitch in a simulated game Monday morning instead of against the Mariners that afternoon in a Cactus League contest.

Taylor Widener will start against the Mariners on Monday. The right-hander is battling for a spot on the roster, presumably in the bullpen, but the team could also decide that he's more valuable to them as starter at their alternate training site or in Triple-A as starting-pitching depth, should one of their starters get injured or reach their innings limit.

Pitching in the less stressful environment of a simulated game will also give Weaver the chance to work and experiment with his pitches more.

Madison Bumgarner's last outing came in a sim game on Wednesday, when he threw more of his secondary offerings than he typically does in a Cactus League game.

"I tried today to do a lot of things that I'm not comfortable with to get more comfortable with them," Bumgarner said afterwards.

Speaking of Bumgarner

With the designated hitter not being used in the National League this year, the D-backs have begun the process of getting their pitchers acclimated to hitting again.

While their hacks have been limited to batting practice to this point, that will change Tuesday when the D-backs stop using the designated hitter in Cactus League games.

Happy birthday, Dave

D-backs first-base coach Dave McKay celebrated his 71st birthday Sunday. He remained at home recovering from a broken rib and lacerated spleen that he sustained on March 8, when he fell in the dugout.

"He is keeping very close tabs with what's going on here through conversations with different coaches [and] myself," Lovullo said. "He watched the game yesterday [on TV]. He noticed that we played good, stole a base and did a lot of good things. So we're keeping him informed. He's feeling better, but still not close to 100 percent. He needs to rest and recover and that's what he's doing right now."