SAN FRANCISCO -- The Cubs went into the season knowing that their bullpen was going to have to carry a heavy workload. The team had a group of relievers build up to multi-inning readiness for that purpose.

Chicago also knew there would be risk involved with a contact-reliant rotation, but the volume of abbreviated starts has been an issue. In a 4-3 loss to the Giants on Saturday at Oracle Park, the bullpen was once again asked to cover more than four frames.

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The Cubs need to correct that trend in their quest for October.

"It taxes the bullpen at some point," Cubs manager David Ross said. "And I think that's where we're at right now."

Ross was referring to the fact that Saturday's game marked the third in a row with a short outing by a Cubs starter. Kohl Stewart lasted only 3 2/3 innings, following a two-inning effort by Jake Arrieta on Friday and 4 1/3 innings from Zach Davies on Thursday.

It did not help that Giants right-hander Kevin Gausman provided a contrasting performance in the Cubs' third straight loss. With his signature splitter, Gausman improved to 7-0 with a 1.27 ERA behind seven innings. He generated 21 whiffs, struck out 10, walked none and flinched once on a two-run homer to Patrick Wisdom.

"We're hitting some homers here and there," Ross said. "But the offense wasn't really on point today. I think that goes a lot to their starting pitcher."

If the Cubs want to maintain a place in the postseason picture down the stretch, targeting starting pitching help could be a priority at the July 30 Trade Deadline. First, there is the matter of not letting this month derail such a scenario.

"The starters, we're trying to step forward," Davies said on Thursday. "And we're trying to carry our own weight and keep this team on a roll."

With that in mind, consider the following:

• Chicago's average fastball velocity (all types) of 91.4 mph by the rotation ranked 29th in the Majors, entering Saturday.

• The rotation also ranked 29th in MLB in strikeout rate (19.4 percent) and swinging-strike rate (9.3 percent).

• The 79.5 percent contact rate allowed by Cubs starters was the third-highest mark in the Majors, while the group's 88.3 percent contact rate on pitches in the zone was the highest in baseball.

• The Cubs' rotation has had 21 starts consisting of fewer than five innings (including Saturday). Entering the day, only the Padres (29) and D-backs (23) had more in the National League.

"I don't think our starting pitchers have the electric stuff that other teams have," Cubs outfielder Joc Pederson said Friday. "But they're very crafty and they know how to pitch. That allows them to be successful."

Look no further than May for evidence to support Pederson's claim. After posting a 5.81 ERA in April, the Cubs' rotation logged a 3.18 ERA in the season's second month. That, combined with an uptick in offensive production, helped ease the burden on the 'pen.

Davies posted a bloated 9.47 ERA in April, be he's since fashioned a 2.52 mark in seven turns. Kyle Hendricks has also enjoyed a turnaround, piecing together a 2.95 ERA in his last six outings (after a 7.54 ERA in April). Adbert Alzolay has also been on a strong run with nine consecutive starts with no more than three runs allowed.

Beyond that trio, Arrieta (8.28 ERA in his last six starts) has labored of late and Trevor Williams (appendectomy) is on the injured list. Stewart is two starts into a stint as the replacement for Williams, who played light catch in San Francisco on Saturday.

So far in June, the starting staff has surrendered 17 runs in 21 innings through five games.

With the bullpen taxed lately, the Cubs summoned starting prospect Cory Abbott from Triple-A Iowa on Saturday, and he turned in two scoreless relief innings. Fellow rookie Keegan Thompson has also found a home in the bullpen, even as another rotation depth piece.

The Cubs do have another depth option in righty Alec Mills (10-day IL, back), who is rehabbing at Triple-A Iowa. Chicago recently lost some depth with Tyson Miller being claimed off waivers by Texas and Shelby Miller requesting his release after being designated for assignment.

A solid outing from Hendricks on Sunday would go a long way in helping the Cubs avoid heading into another tough road series with the Padres.

"I have a lot of trust in these guys -- our staff," Kris Bryant said this weekend.