NEW YORK ( TheStreet) -- A lackluster reading on the government's monthly jobs report Friday could deal another blow to already weakening global markets. With stocks plunging more than 4%, and the Dowtumbling 500 points Thursday, investors are struggling to find reasons to be optimistic. A recent report from Standard & Poor's said that tomorrow will be key in determining "the risk of recession." S&P strategist Sam Stovall said that market declines alone aren't enough to signal a recession. However, "unrelenting stock price declines that are accompanied by weaker-than-expected GDP, manufacturing activity and jobs data add to existing concerns." "If jobs growth is negative tomorrow, markets will be crushed," says Robert Johnson, economist at Morningstar. In the worst case scenario, Johnson thinks markets could drop as much as 5%. Weekly unemployment claims have been mired around the 400,000 mark, and earlier this week Automatic Data Processing reported that companies added 114,000 new jobs in July. Given that other parts of the economy -- manufacturing, services and consumer spending -- put in a lackluster performance in June and July, the market has set a low bar on the jobs front. The unemployment rate is expected to remain stuck at 9.2%, according to consensus estimate. Economists are calling for 84,000 new jobs in total and 100,000 new jobs in the private sector for July. Briefing.com is expecting a total of 50,000 new jobs, 75,000 in the private sector. Manufacturing is likely to have slashed payrolls after a slump in July manufacturing activity . Cutbacks in local and state spending are expected to drag down numbers as well, as the public sector tends to contract more in the summer months. Investors were stunned in July when the Bureau of Labor said the economy added only 18,000 new jobs in June, with unemployment inching up to 9.2% from 9.1%. Expectations had been raised when only days earlier Automatic Data Processing said companies added 157,000 jobs in June. This time around, economists are more reluctant to play weatherman. "I've given up trying to guess," said Peter Boockvar, equity strategist at Miller Tabak & Co. Boockvar also notes that the government revises payroll numbers multiple times after they're published. On the upside, there are a few nuggets of data that suggest the economy is not going to fall into an abyss. Johnson of Morningstar points to dramatically higher auto sales in June and personal income levels, which rose in June to the highest rate this year. Disappointing numbers on Friday would easily fuel beliefs that the economy is headed for a double-dip. Therefore, if the report comes in line with estimates, Boockvar of Miller Tabak says that investors will be sighing a breath of relief. -- Written by Chao Deng in New York. >To contact the writer of this article, click here: Chao Deng.